Pub Date : 2025-10-14DOI: 10.1016/j.jmatprotec.2025.119100
Hao Wang, Guoliang Qin, Banglong Fu, Changan Li, Baiyun Yang
The inherent radial non-uniformity of thermo-mechanical distribution in conventional rotary friction welding (RFW) of bar joints leads to heterogeneous microstructures and compromised mechanical properties. A tapered end-face design can actively regulate the thermo-mechanical coupling process, addressing the critical challenge of joint performance inconsistency. This study develops a three-dimensional thermal-mechanical coupled finite element model to elucidate the influencing mechanism of end-face design on the Al alloy/steel RFW process. The model accurately predicts interface temperature evolution and joint deformation, enabling quantitative analysis of spatial variations in thermo-mechanical fields. Results reveal that tapering the Al alloy end-face elevates the interface temperature at the center region by promoting plastic deformation under high contact pressure while restricting excessive material outflow. Furthermore, a tapering steel end-face with a small platform is identified as optimal for improving temperature uniformity and removing initial interface material. This work establishes a mechanistic link between end-face geometry, heat generation, and material flow, thereby providing a design-oriented framework for achieving homogeneous joints in dissimilar-metal RFW.
{"title":"Mechanism of thermo-mechanical uniformity enhancement in dissimilar metal rotary friction welding via end-face geometry optimization","authors":"Hao Wang, Guoliang Qin, Banglong Fu, Changan Li, Baiyun Yang","doi":"10.1016/j.jmatprotec.2025.119100","DOIUrl":"10.1016/j.jmatprotec.2025.119100","url":null,"abstract":"<div><div>The inherent radial non-uniformity of thermo-mechanical distribution in conventional rotary friction welding (RFW) of bar joints leads to heterogeneous microstructures and compromised mechanical properties. A tapered end-face design can actively regulate the thermo-mechanical coupling process, addressing the critical challenge of joint performance inconsistency. This study develops a three-dimensional thermal-mechanical coupled finite element model to elucidate the influencing mechanism of end-face design on the Al alloy/steel RFW process. The model accurately predicts interface temperature evolution and joint deformation, enabling quantitative analysis of spatial variations in thermo-mechanical fields. Results reveal that tapering the Al alloy end-face elevates the interface temperature at the center region by promoting plastic deformation under high contact pressure while restricting excessive material outflow. Furthermore, a tapering steel end-face with a small platform is identified as optimal for improving temperature uniformity and removing initial interface material. This work establishes a mechanistic link between end-face geometry, heat generation, and material flow, thereby providing a design-oriented framework for achieving homogeneous joints in dissimilar-metal RFW.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"346 ","pages":"Article 119100"},"PeriodicalIF":7.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-14DOI: 10.1016/j.jmatprotec.2025.119105
Kai Tang , Dongdong Gu , Lixia Xi , Keyu Shi , Jiaxing Hou , Han Zhang
The defocusing distance significantly influences the solidification process and microstructural evolution of Al-Cu alloy in powder bed fusion by laser beam melting (PBF-LBM). To investigate this, a computational fluid dynamics-melt pool geometry-phase field (CFD-GPF) model was established to analyze the effects of defocusing distance on flow fields, temperature fields, and microstructure evolution during the PBF-LBM processing of 2024 alloy. Simulation results indicated that as the defocusing distance increased from −2 mm to 2 mm, the melt pool depth changed from 52 ± 3 μm to 45 ± 2 μm. The melting mode transitioned from conduction to keyhole, then returned to conduction mode. Notably, under negative defocusing, the melt pool depth increased significantly. Flow and temperature field patterns showed the similar trends. These changes facilitated the transformation of grains from the columnar grains to the fine, uniform equiaxed structures. Electron backscatter diffraction results showed the average grain size of the sample with a defocusing distance of 0 mm was 27.68 μm, while with a defocusing distance of the 2 mm sample was 13.39 μm, representing a 52 % reduction. When the defocusing distance increased from 0 mm to 2 mm, the proportion of equiaxed grains increased from 51.52 % to 68.69 %. The Kernel Average Misorientation analysis revealed that increasing the defocusing distance from 0 mm to 2 mm led to a reduction in intergranular residual stress, which is beneficial for mitigating crack formation. This study indicates that defocusing distance is an important parameter for controlling melt pool size and microstructure during PBF-LBM processing.
{"title":"Revealing underlying effect of beam defocusing on powder bed fusion by laser beam melting of Al-Cu alloy using multi-physics coupling modelling and experimental verification","authors":"Kai Tang , Dongdong Gu , Lixia Xi , Keyu Shi , Jiaxing Hou , Han Zhang","doi":"10.1016/j.jmatprotec.2025.119105","DOIUrl":"10.1016/j.jmatprotec.2025.119105","url":null,"abstract":"<div><div>The defocusing distance significantly influences the solidification process and microstructural evolution of Al-Cu alloy in powder bed fusion by laser beam melting (PBF-LBM). To investigate this, a computational fluid dynamics-melt pool geometry-phase field (CFD-GPF) model was established to analyze the effects of defocusing distance on flow fields, temperature fields, and microstructure evolution during the PBF-LBM processing of 2024 alloy. Simulation results indicated that as the defocusing distance increased from −2 mm to 2 mm, the melt pool depth changed from 52 ± 3 μm to 45 ± 2 μm. The melting mode transitioned from conduction to keyhole, then returned to conduction mode. Notably, under negative defocusing, the melt pool depth increased significantly. Flow and temperature field patterns showed the similar trends. These changes facilitated the transformation of grains from the columnar grains to the fine, uniform equiaxed structures. Electron backscatter diffraction results showed the average grain size of the sample with a defocusing distance of 0 mm was 27.68 μm, while with a defocusing distance of the 2 mm sample was 13.39 μm, representing a 52 % reduction. When the defocusing distance increased from 0 mm to 2 mm, the proportion of equiaxed grains increased from 51.52 % to 68.69 %. The Kernel Average Misorientation analysis revealed that increasing the defocusing distance from 0 mm to 2 mm led to a reduction in intergranular residual stress, which is beneficial for mitigating crack formation. This study indicates that defocusing distance is an important parameter for controlling melt pool size and microstructure during PBF-LBM processing.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"346 ","pages":"Article 119105"},"PeriodicalIF":7.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-14DOI: 10.1016/j.jmatprotec.2025.119101
Tianlong Gao , Bo Yuan , Hongge Li , Zhiwen Xie , Liang Zhang , Chuang Li , Zhiheng Jiang , Houyi Bai , Zhiqiang Ding , Jiajia Cao
Arc-cladding Babbitt alloys are widely used in sliding bearings for wind power generation owing to their cost-effectiveness and high material efficiency. However, insufficient interfacial bonding strength between Babbitt alloys and steel has long been a persistent issue, hindering the production of high-quality claddings. Given that the specific effects of pulsed current on the growth behaviour and mechanisms of interfacial compounds remain unclear, we employed pulsed current-assisted arc cladding to deposit a Babbitt alloy onto a CuAl10Fe1 layer, yielding a ZSnSb8Cu4-CuAl10Fe1–42CrMo4 tri-layer heterogeneous structure composite. Furthermore, we elucidated the universal regulation of interface coherency by varying the number of pulses. When the pulse count was set to 10, the degree of misfit was maintained within 5 %, enabling directional growth of coherent nanoprecipitates. The prepared synergistic, heterogeneous gradient structure achieved a balance between strength and ductility, with the microhardness progressively increasing from the ZSnSb8Cu4 layer to the 42CrMo4 substrate. The composite demonstrated excellent comprehensive performance, with tensile yield strength, ultimate tensile strength and elongation at break of 661.5 ± 2.9 MPa, 817.4 ± 3.1 MPa and 13.9 % ± 0.9 %, respectively. The interfacial bonding strengths of the CuAl10Fe1–42CrMo4 and ZSnSb8Cu4-CuAl10Fe1 interfaces were 43.7 ± 1.3 and 145.6 ± 7.3 MPa, respectively. The enhanced performance of the composite was attributed to mechanisms, such as coherency effects of CuAl, precipitation strengthening, grain refinement, all induced by non-thermal effects. Results provide valuable insights for designing and manufacturing heterogeneous structure composites for sliding bearings.
{"title":"Microstructural evolution and mechanical properties of pulsed current-assisted Arc cladding tri-layer Babbitt alloy-Cu-steel heterogeneous structure composite","authors":"Tianlong Gao , Bo Yuan , Hongge Li , Zhiwen Xie , Liang Zhang , Chuang Li , Zhiheng Jiang , Houyi Bai , Zhiqiang Ding , Jiajia Cao","doi":"10.1016/j.jmatprotec.2025.119101","DOIUrl":"10.1016/j.jmatprotec.2025.119101","url":null,"abstract":"<div><div>Arc-cladding Babbitt alloys are widely used in sliding bearings for wind power generation owing to their cost-effectiveness and high material efficiency. However, insufficient interfacial bonding strength between Babbitt alloys and steel has long been a persistent issue, hindering the production of high-quality claddings. Given that the specific effects of pulsed current on the growth behaviour and mechanisms of interfacial compounds remain unclear, we employed pulsed current-assisted arc cladding to deposit a Babbitt alloy onto a CuAl10Fe1 layer, yielding a ZSnSb8Cu4-CuAl10Fe1–42CrMo4 tri-layer heterogeneous structure composite. Furthermore, we elucidated the universal regulation of interface coherency by varying the number of pulses. When the pulse count was set to 10, the degree of misfit was maintained within 5 %, enabling directional growth of coherent nanoprecipitates. The prepared synergistic, heterogeneous gradient structure achieved a balance between strength and ductility, with the microhardness progressively increasing from the ZSnSb8Cu4 layer to the 42CrMo4 substrate. The composite demonstrated excellent comprehensive performance, with tensile yield strength, ultimate tensile strength and elongation at break of 661.5 ± 2.9 MPa, 817.4 ± 3.1 MPa and 13.9 % ± 0.9 %, respectively. The interfacial bonding strengths of the CuAl10Fe1–42CrMo4 and ZSnSb8Cu4-CuAl10Fe1 interfaces were 43.7 ± 1.3 and 145.6 ± 7.3 MPa, respectively. The enhanced performance of the composite was attributed to mechanisms, such as coherency effects of CuAl, precipitation strengthening, grain refinement, all induced by non-thermal effects. Results provide valuable insights for designing and manufacturing heterogeneous structure composites for sliding bearings.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"346 ","pages":"Article 119101"},"PeriodicalIF":7.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145360109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-14DOI: 10.1016/j.jmatprotec.2025.119106
Zhisen Ye , Xiaolei Chen , Yonghua Zhao , Long Ye , Yongjun Zhang
Electrochemical drilling (ECD) has become one of the most suitable technologies for fabricating holes in difficult-to-machine materials owing to its excellent surface integrity and absence of tool wear. However, the narrow inter-electrode gap (IEG) causes severe flow velocity loss and induces a low-velocity zone, hindering the expulsion of electrolytic products and reducing machining performance. This paper proposes a novel ECD method that couples pulsating flow and electric fields in the same phase and frequency. A modified tube tool with partially insulated toothed end face (TE-tube tool) is designed, which can be rotated to induce temporal and spatial pulsations of both flow and electric fields within IEG. The pulsating electric field disperses electrolytic products, while the pulsating flow field enhances flushing. This coupling improves electrochemical dissolution and enhances machining quality. Simulations indicate that within machining zone, flow velocity and current density exhibit similar sine-wave patterns, leading to material removal at high current densities coupled with high flow velocities, advancing electrolytic product removal and improved surface quality. The toothed tool end face also induces a flow diversion effect, effectively eliminating the low-velocity zone and improving machining stability. Experimental results indicate that compared to traditional ECD, the proposed method achieves a more stable machining current without electrolytic products adherence in the tube tool, a 69 % improvement in surface quality, and an 72 % reduction in dimensional deviation. Meanwhile, the enlarged frontal IEG created by insulated toothed face causes a transition in current density distribution characteristics from ECD to electrochemical jet machining (EJM), contributing to a more concentrated machining electric field and thereby improving hole entrance morphology. Furthermore, the superior flushing effect enables the maximum feed rate to reach 2.4 mm/min, representing a 54 % increase in machining efficiency. This study demonstrates the effectiveness of coupling pulsating flow and electric fields in ECD for high-quality small-hole manufacturing.
{"title":"Realization of pulsating flow and electric fields coupled in same phase and co-frequency to enhance electrochemical drilling","authors":"Zhisen Ye , Xiaolei Chen , Yonghua Zhao , Long Ye , Yongjun Zhang","doi":"10.1016/j.jmatprotec.2025.119106","DOIUrl":"10.1016/j.jmatprotec.2025.119106","url":null,"abstract":"<div><div>Electrochemical drilling (ECD) has become one of the most suitable technologies for fabricating holes in difficult-to-machine materials owing to its excellent surface integrity and absence of tool wear. However, the narrow inter-electrode gap (IEG) causes severe flow velocity loss and induces a low-velocity zone, hindering the expulsion of electrolytic products and reducing machining performance. This paper proposes a novel ECD method that couples pulsating flow and electric fields in the same phase and frequency. A modified tube tool with partially insulated toothed end face (TE-tube tool) is designed, which can be rotated to induce temporal and spatial pulsations of both flow and electric fields within IEG. The pulsating electric field disperses electrolytic products, while the pulsating flow field enhances flushing. This coupling improves electrochemical dissolution and enhances machining quality. Simulations indicate that within machining zone, flow velocity and current density exhibit similar sine-wave patterns, leading to material removal at high current densities coupled with high flow velocities, advancing electrolytic product removal and improved surface quality. The toothed tool end face also induces a flow diversion effect, effectively eliminating the low-velocity zone and improving machining stability. Experimental results indicate that compared to traditional ECD, the proposed method achieves a more stable machining current without electrolytic products adherence in the tube tool, a 69 % improvement in surface quality, and an 72 % reduction in dimensional deviation. Meanwhile, the enlarged frontal IEG created by insulated toothed face causes a transition in current density distribution characteristics from ECD to electrochemical jet machining (EJM), contributing to a more concentrated machining electric field and thereby improving hole entrance morphology. Furthermore, the superior flushing effect enables the maximum feed rate to reach 2.4 mm/min, representing a 54 % increase in machining efficiency. This study demonstrates the effectiveness of coupling pulsating flow and electric fields in ECD for high-quality small-hole manufacturing.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"346 ","pages":"Article 119106"},"PeriodicalIF":7.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-14DOI: 10.1016/j.jmatprotec.2025.119104
Xingyi Li , Tianxiao Zhu , Yiran Li , Yanyu Song , Duo Liu , Zhuolin Li , Xiaoguo Song , Junghoon Lee , Dongsik Kim
Graphite components serve as irreplaceable structural and functional parts in multiple engineering applications. However, the necessary processing requirements, including high temperatures (∼850 °C), prolonged durations (several hours), and high-vacuum conditions, pose significant challenges for the efficient manufacturing of graphite components. Aiming to achieve the rapid bonding of graphite (pyrolytic graphite (PG) and porous graphite (G)), a novel two-step method that combines ultrasonic-vibration–assisted metallization with dip soldering is proposed in this study. The surfaces of PG and G are metallized by an Sn Ti (ST) alloy under ultrasonic vibrations at 300 °C within 10 s in air. Under an oxygen-containing conditions, the active Ti from the ST melt preferentially reacts with O to form an amorphous nanocrystalline TiO₂ transition layer, which plays a decisive role in establishing metallurgical bonding and transmitting loads and heat flux between the graphite and ST alloy. The soldered joints exhibit exceptional property retention, with PG/PG and G/G joints maintaining equal and 98 % (21.8 MPa) of the shear strength, and 93 % (389 W/m·K) and 92 % (105 W/m·K) of the thermal conductivity, respectively, of the base materials. The proposed two-step method offers an efficient approach for the rapid manufacture of graphite components, addressing key challenges in graphite-bonding technology.
{"title":"Interfacial behaviours of Sn-Ti/graphite system bonded via ultrasonic-vibration–assisted metallization","authors":"Xingyi Li , Tianxiao Zhu , Yiran Li , Yanyu Song , Duo Liu , Zhuolin Li , Xiaoguo Song , Junghoon Lee , Dongsik Kim","doi":"10.1016/j.jmatprotec.2025.119104","DOIUrl":"10.1016/j.jmatprotec.2025.119104","url":null,"abstract":"<div><div>Graphite components serve as irreplaceable structural and functional parts in multiple engineering applications. However, the necessary processing requirements, including high temperatures (∼850 °C), prolonged durations (several hours), and high-vacuum conditions, pose significant challenges for the efficient manufacturing of graphite components. Aiming to achieve the rapid bonding of graphite (pyrolytic graphite (PG) and porous graphite (G)), a novel two-step method that combines ultrasonic-vibration–assisted metallization with dip soldering is proposed in this study. The surfaces of PG and G are metallized by an Sn Ti (ST) alloy under ultrasonic vibrations at 300 °C within 10 s in air. Under an oxygen-containing conditions, the active Ti from the ST melt preferentially reacts with O to form an amorphous nanocrystalline TiO₂ transition layer, which plays a decisive role in establishing metallurgical bonding and transmitting loads and heat flux between the graphite and ST alloy. The soldered joints exhibit exceptional property retention, with PG/PG and G/G joints maintaining equal and 98 % (21.8 MPa) of the shear strength, and 93 % (389 W/m·K) and 92 % (105 W/m·K) of the thermal conductivity, respectively, of the base materials. The proposed two-step method offers an efficient approach for the rapid manufacture of graphite components, addressing key challenges in graphite-bonding technology.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"346 ","pages":"Article 119104"},"PeriodicalIF":7.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-14DOI: 10.1016/j.jmatprotec.2025.119103
Hongyu Long , Yang Li , Yujuan Wu , Yiling Lian , Jun Zhou , Xiaoyu Liang , Feng Lin
This study addresses the inherent conflict between high crack susceptibility and microstructural coarsening in the electron beam powder bed fusion of the non-weldable nickel-based superalloy MAR-M247 by proposing an innovative microstructural design strategy. By actively leveraging the unique characteristics of EB-PBF—including its high preheating capability (>1100°C) and low cooling rate—elemental segregation, traditionally considered detrimental, was transformed into a beneficial tool for microstructural control. This approach successfully induced the in-situ precipitation of nano-carbides and constructed a geometrically interlocked, dovetail-like grain boundary architecture. Under optimized parameters (preheating: 1050°C, energy density: 2 J/mm²), crack-free dense samples were achieved, with dendritic width and MC carbide size reduced by 67.57 % and 44.11 %, respectively. The interlocked structure enhances load transfer, improves strain coordination, and dissipates energy through crack deflection and branching, significantly improving ductility without sacrificing strength. Horizontal samples showed excellent strength–ductility synergy (UTS: 1269 MPa, elongation: 19.57 %), surpassing cast and post-processed counterparts. Through thermodynamic calculations and experimental validation, the non-equilibrium solidification pathway, phase evolution, and deformation mechanisms were systematically elucidated—e.g., dislocation shearing of γ′ phases forming anti-phase boundaries (APBs) at room temperature, and Orowan looping dominating at elevated temperatures. This work not only provides a reliable processing window and theoretical foundation for EB-PBF fabrication of high-performance non-weldable superalloys but also proposes a universal paradigm of "harnessing process characteristics to drive microstructural design." This strategy is applicable to other additive manufacturing techniques with low cooling rates (e.g., directional solidification, laser cladding).
{"title":"Achieving crack-free and strong-ductile Ni-based superalloys via harnessing segregation to create interlocking microstructures during electron beam additive manufacturing","authors":"Hongyu Long , Yang Li , Yujuan Wu , Yiling Lian , Jun Zhou , Xiaoyu Liang , Feng Lin","doi":"10.1016/j.jmatprotec.2025.119103","DOIUrl":"10.1016/j.jmatprotec.2025.119103","url":null,"abstract":"<div><div>This study addresses the inherent conflict between high crack susceptibility and microstructural coarsening in the electron beam powder bed fusion of the non-weldable nickel-based superalloy MAR-M247 by proposing an innovative microstructural design strategy. By actively leveraging the unique characteristics of EB-PBF—including its high preheating capability (>1100°C) and low cooling rate—elemental segregation, traditionally considered detrimental, was transformed into a beneficial tool for microstructural control. This approach successfully induced the in-situ precipitation of nano-carbides and constructed a geometrically interlocked, dovetail-like grain boundary architecture. Under optimized parameters (preheating: 1050°C, energy density: 2 J/mm²), crack-free dense samples were achieved, with dendritic width and MC carbide size reduced by 67.57 % and 44.11 %, respectively. The interlocked structure enhances load transfer, improves strain coordination, and dissipates energy through crack deflection and branching, significantly improving ductility without sacrificing strength. Horizontal samples showed excellent strength–ductility synergy (UTS: 1269 MPa, elongation: 19.57 %), surpassing cast and post-processed counterparts. Through thermodynamic calculations and experimental validation, the non-equilibrium solidification pathway, phase evolution, and deformation mechanisms were systematically elucidated—e.g., dislocation shearing of γ′ phases forming anti-phase boundaries (APBs) at room temperature, and Orowan looping dominating at elevated temperatures. This work not only provides a reliable processing window and theoretical foundation for EB-PBF fabrication of high-performance non-weldable superalloys but also proposes a universal paradigm of \"harnessing process characteristics to drive microstructural design.\" This strategy is applicable to other additive manufacturing techniques with low cooling rates (e.g., directional solidification, laser cladding).</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"346 ","pages":"Article 119103"},"PeriodicalIF":7.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-06DOI: 10.1016/j.jmatprotec.2025.119097
Tiancheng Ai , Dongdong Xu , Liming Lei , Wei Zhang , Wentao Qin , Zhirong Liao
Metal matrix composites (MMCs) have attracted considerable research interest for their applications in the aerospace, automotive, and semiconductor industries. However, MMCs present significant challenges in machining, with surface quality remaining a key bottleneck. Water jet-guided laser (WJGL) machining emerges as a promising hybrid technique, which is highly suitable for machining these difficult-to-process materials. Nevertheless, the fundamental mechanisms of WJGL machining MMCs remain inadequately understood, including the surface morphologies, reaction mechanisms, and chemical reactions. To address these issues, this study investigates the machining effects and mechanisms by machining holes in aluminum matrix composites reinforced with silicon carbide particles (Al/SiCp MMCs) by WJGL machining. The results demonstrate that the WJGL enables high-precision machining of micro-holes, with dimensional errors stabilized within a narrow range of 135–164 μm and entry roundness errors as low as 8–15 μm. The synergy between laser and water jet results in smooth, burr free surfaces, with sidewalls exhibiting periodic ripples pattern and pits, and their formation mechanisms are explained in this study. Multiscale analyses revealed the formation of complex compounds and partial decomposition of silicon carbide, along with evidence of oxidation reactions. The heat-affected zone (HAZ) in the subsurface region was extremely narrow, with an average width of 14.2 μm. The SiC particles in the HAZ are subjected to thermal and mechanical loads, which can lead to their fracture and ultimately affect the material properties in this region.
{"title":"Mechanism of water jet-guided laser machining of Al/SiCp metal matrix composites","authors":"Tiancheng Ai , Dongdong Xu , Liming Lei , Wei Zhang , Wentao Qin , Zhirong Liao","doi":"10.1016/j.jmatprotec.2025.119097","DOIUrl":"10.1016/j.jmatprotec.2025.119097","url":null,"abstract":"<div><div>Metal matrix composites (MMCs) have attracted considerable research interest for their applications in the aerospace, automotive, and semiconductor industries. However, MMCs present significant challenges in machining, with surface quality remaining a key bottleneck. Water jet-guided laser (WJGL) machining emerges as a promising hybrid technique, which is highly suitable for machining these difficult-to-process materials. Nevertheless, the fundamental mechanisms of WJGL machining MMCs remain inadequately understood, including the surface morphologies, reaction mechanisms, and chemical reactions. To address these issues, this study investigates the machining effects and mechanisms by machining holes in aluminum matrix composites reinforced with silicon carbide particles (Al/SiCp MMCs) by WJGL machining. The results demonstrate that the WJGL enables high-precision machining of micro-holes, with dimensional errors stabilized within a narrow range of 135–164 μm and entry roundness errors as low as 8–15 μm. The synergy between laser and water jet results in smooth, burr free surfaces, with sidewalls exhibiting periodic ripples pattern and pits, and their formation mechanisms are explained in this study. Multiscale analyses revealed the formation of complex compounds and partial decomposition of silicon carbide, along with evidence of oxidation reactions. The heat-affected zone (HAZ) in the subsurface region was extremely narrow, with an average width of 14.2 μm. The SiC particles in the HAZ are subjected to thermal and mechanical loads, which can lead to their fracture and ultimately affect the material properties in this region.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"346 ","pages":"Article 119097"},"PeriodicalIF":7.5,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145236185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-06DOI: 10.1016/j.jmatprotec.2025.119098
Yaxing Tong , Guoliang Zhu , Sanbao Lin
Laser powder bed fusion (LPBF) imparts nickel-based superalloys with unique non-equilibrium microstructural features; however, their influence on the welding microstructure evolution and mechanical performance remains insufficiently understood. In this study, autogenous gas tungsten arc welding was applied to precipitation-strengthened ZGH4142 superalloy fabricated by LPBF. Microstructural characterization combined with finite element simulation was used to systematically clarify the effects of heat input and welding direction on the structure and properties of the welded joint. The results revealed that the weld morphology and pool geometry enlarged with increasing heat input, and fine equiaxed grains in the weld center transformed to coarse equiaxed ones. With decreasing cooling rate, the MC carbides coarsened, while the γ′ fraction increased from 14 % to 33 %, shifting the dominant strengthening mechanism from grain refinement to dislocation strengthening. The joints exhibited a typical “M-shaped” hardness profile, with the heat-affected zone (HAZ) and weld zone (WZ) showing the highest and lowest hardness, respectively. Quantitative strengthening analysis indicated that the base metal and WZ were mainly governed by solid-solution strengthening, and the HAZ exhibited predominantly dislocation strengthening. Electron backscattered diffraction analysis further revealed that the grain orientation and low-angle grain boundary fractions were sensitive to the welding direction, reflecting the intrinsic anisotropy of the LPBF-processed alloys. These findings provide fundamental insights and practical guidance for welding evaluation and process optimization of additively manufactured nickel-based superalloys.
{"title":"Microstructural evolution and strengthening mechanisms of gas tungsten arc welded nickel-based superalloy joints processed by laser powder bed fusion: Effects of welding direction and heat input","authors":"Yaxing Tong , Guoliang Zhu , Sanbao Lin","doi":"10.1016/j.jmatprotec.2025.119098","DOIUrl":"10.1016/j.jmatprotec.2025.119098","url":null,"abstract":"<div><div>Laser powder bed fusion (LPBF) imparts nickel-based superalloys with unique non-equilibrium microstructural features; however, their influence on the welding microstructure evolution and mechanical performance remains insufficiently understood. In this study, autogenous gas tungsten arc welding was applied to precipitation-strengthened ZGH4142 superalloy fabricated by LPBF. Microstructural characterization combined with finite element simulation was used to systematically clarify the effects of heat input and welding direction on the structure and properties of the welded joint. The results revealed that the weld morphology and pool geometry enlarged with increasing heat input, and fine equiaxed grains in the weld center transformed to coarse equiaxed ones. With decreasing cooling rate, the MC carbides coarsened, while the γ′ fraction increased from 14 % to 33 %, shifting the dominant strengthening mechanism from grain refinement to dislocation strengthening. The joints exhibited a typical “M-shaped” hardness profile, with the heat-affected zone (HAZ) and weld zone (WZ) showing the highest and lowest hardness, respectively. Quantitative strengthening analysis indicated that the base metal and WZ were mainly governed by solid-solution strengthening, and the HAZ exhibited predominantly dislocation strengthening. Electron backscattered diffraction analysis further revealed that the grain orientation and low-angle grain boundary fractions were sensitive to the welding direction, reflecting the intrinsic anisotropy of the LPBF-processed alloys. These findings provide fundamental insights and practical guidance for welding evaluation and process optimization of additively manufactured nickel-based superalloys.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"346 ","pages":"Article 119098"},"PeriodicalIF":7.5,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145236187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-03DOI: 10.1016/j.jmatprotec.2025.119087
Yongchao Xu , Zichen Fan , Dairui Yang , Zige Tian , Qianting Wang , Youji Zhan , Bingsan Chen
In this study, the influence of an oxygen-rich environment on polishing performance and tribo-chemical removal mechanism during sapphire chemical mechanical polishing (CMP) was systematically investigated through self-designed gas-assisted CMP (GA-CMP) equipment. Polishing slurry with varying dissolved oxygen (DO) concentrations were prepared using the aforementioned system. The effects of dissolved oxygen levels on polishing conditions were analyzed by evaluating the reactivity of oxygen-enriched slurries, dispersion stability of abrasives, coefficient of friction (COF) at the sapphire-polishing interface, and wettability on sapphire surfaces. Subsequently, CMP experiments under oxygen-rich conditions were conducted to elucidate the impact of oxygen assistance on polishing efficiency and removal mechanisms. When the dissolved oxygen concentration in the polishing slurry is increased to 40 ppm, sapphire achieves optimal processing performance: the reaction activity and abrasive dispersibility of the polishing slurry, as well as the wettability and friction coefficient of the sapphire surface, are significantly enhanced. The surface roughness of the processed sapphire decreases by 57.3 % to 0.124 nm compared with that under traditional CMP, and the material removal rate increases by 23.02 %. Through phase composition analysis of the processed sapphire surface and morphology analysis of the polishing debris, it is concluded that the oxygen-rich environment significantly promotes the chemical reaction process at the processing interface. A soft reaction layer composed of AlOOH, Al2SiO5 and AlOx is formed on the Al2O3 surface. The tribo-chemical removal mechanism primarily involves the formation of soft reaction layer, which is then detached from the wafer surface under the mechanical scratching action of abrasive particles. In summary, the introduction of an oxygen-rich environment significantly optimizes processing conditions such as the reaction activity of the polishing slurry, abrasive dispersibility, and wafer surface wettability. By enhancing the chemical reaction intensity at the processing interface, it remarkably improves the processing efficiency and quality of the wafer surface, enabling high-efficiency and precision machining of single-crystal sapphire.
{"title":"Enhanced polishing performance and tribo-chemical removal mechanism of sapphire wafers under gas-assisted CMP (GA-CMP)","authors":"Yongchao Xu , Zichen Fan , Dairui Yang , Zige Tian , Qianting Wang , Youji Zhan , Bingsan Chen","doi":"10.1016/j.jmatprotec.2025.119087","DOIUrl":"10.1016/j.jmatprotec.2025.119087","url":null,"abstract":"<div><div>In this study, the influence of an oxygen-rich environment on polishing performance and tribo-chemical removal mechanism during sapphire chemical mechanical polishing (CMP) was systematically investigated through self-designed gas-assisted CMP (GA-CMP) equipment. Polishing slurry with varying dissolved oxygen (DO) concentrations were prepared using the aforementioned system. The effects of dissolved oxygen levels on polishing conditions were analyzed by evaluating the reactivity of oxygen-enriched slurries, dispersion stability of abrasives, coefficient of friction (COF) at the sapphire-polishing interface, and wettability on sapphire surfaces. Subsequently, CMP experiments under oxygen-rich conditions were conducted to elucidate the impact of oxygen assistance on polishing efficiency and removal mechanisms. When the dissolved oxygen concentration in the polishing slurry is increased to 40 ppm, sapphire achieves optimal processing performance: the reaction activity and abrasive dispersibility of the polishing slurry, as well as the wettability and friction coefficient of the sapphire surface, are significantly enhanced. The surface roughness of the processed sapphire decreases by 57.3 % to 0.124 nm compared with that under traditional CMP, and the material removal rate increases by 23.02 %. Through phase composition analysis of the processed sapphire surface and morphology analysis of the polishing debris, it is concluded that the oxygen-rich environment significantly promotes the chemical reaction process at the processing interface. A soft reaction layer composed of AlOOH, Al<sub>2</sub>SiO<sub>5</sub> and AlO<sub>x</sub> is formed on the Al<sub>2</sub>O<sub>3</sub> surface. The tribo-chemical removal mechanism primarily involves the formation of soft reaction layer, which is then detached from the wafer surface under the mechanical scratching action of abrasive particles. In summary, the introduction of an oxygen-rich environment significantly optimizes processing conditions such as the reaction activity of the polishing slurry, abrasive dispersibility, and wafer surface wettability. By enhancing the chemical reaction intensity at the processing interface, it remarkably improves the processing efficiency and quality of the wafer surface, enabling high-efficiency and precision machining of single-crystal sapphire.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"346 ","pages":"Article 119087"},"PeriodicalIF":7.5,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The development of reusable spacecraft imposes stringent requirements on the structural reliability and reusability of thermal protection systems (TPS). Conventional TPS designs typically employ multi-layer configurations with metallic substrates, ceramic layers, and ablative insulation. However, these “sandwich” structures are prone to failure due to inadequate interlayer bonding or irreversible damage, while metallic frameworks bonded with ceramic tiles exhibit compromised reliability. To address these challenges, this study employs directed energy deposition (DED) to fabricate Ti6Al4V / YSZ gradient materials through compositional design, aiming to enhance ablation resistance and thermal insulation. Results demonstrate that defect-free samples with YSZ content (0–30 wt%) can be fabricated using linear, piecewise linear, and nonlinear compositional gradient strategies. The gradient materials exhibit an average mass ablation rate below 0.2 mg/s, average linear ablation rate below 0.95 μm/s, and thermal diffusivity below 0.047 cm2/s. The enhanced ablation resistance originates from a dense TiO2 - ZrO2 - (Ti, Zr)O2 oxide layer that impedes erosion, while the compositional gradient prevents spalling. Improved thermal insulation results from enhanced phonon and electron scattering by in-situ generated t-ZrO2, c-ZrO2, and Y2O3 phases, and tortuous heat flow paths. This research validates DED feasibility for high-ceramic-content Ti / YSZ materials and provides new insights for reusable spacecraft TPS design.
{"title":"Synergistically enhanced ablation resistance and thermal insulation in Ti6Al4V / YSZ gradient materials fabricated by direct energy deposition","authors":"Mengyi Cao, Leilei Wang, Jiahao Zhang, Yanxiao Zhang, Xiaohong Zhan, Zhoucheng Liu","doi":"10.1016/j.jmatprotec.2025.119086","DOIUrl":"10.1016/j.jmatprotec.2025.119086","url":null,"abstract":"<div><div>The development of reusable spacecraft imposes stringent requirements on the structural reliability and reusability of thermal protection systems (TPS). Conventional TPS designs typically employ multi-layer configurations with metallic substrates, ceramic layers, and ablative insulation. However, these “sandwich” structures are prone to failure due to inadequate interlayer bonding or irreversible damage, while metallic frameworks bonded with ceramic tiles exhibit compromised reliability. To address these challenges, this study employs directed energy deposition (DED) to fabricate Ti6Al4V / YSZ gradient materials through compositional design, aiming to enhance ablation resistance and thermal insulation. Results demonstrate that defect-free samples with YSZ content (0–30 wt%) can be fabricated using linear, piecewise linear, and nonlinear compositional gradient strategies. The gradient materials exhibit an average mass ablation rate below 0.2 mg/s, average linear ablation rate below 0.95 μm/s, and thermal diffusivity below 0.047 cm<sup>2</sup>/s. The enhanced ablation resistance originates from a dense TiO<sub>2</sub> - ZrO<sub>2</sub> - (Ti, Zr)O<sub>2</sub> oxide layer that impedes erosion, while the compositional gradient prevents spalling. Improved thermal insulation results from enhanced phonon and electron scattering by in-situ generated t-ZrO<sub>2</sub>, c-ZrO<sub>2</sub>, and Y<sub>2</sub>O<sub>3</sub> phases, and tortuous heat flow paths. This research validates DED feasibility for high-ceramic-content Ti / YSZ materials and provides new insights for reusable spacecraft TPS design.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"346 ","pages":"Article 119086"},"PeriodicalIF":7.5,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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