The dual precipitation of NiAl particles and M2C carbides during ageing plays a critical role in achieving an optimal balance of strength and toughness in low-cobalt secondary hardening steel, yet this remains scarcely investigated. This work investigates the evolution of NiAl and M2C during ageing at 482 °C for durations ranging from 1 h to 150 h, focusing on their influence on the strength and impact toughness of martensitic steel. It was found that after 5 h of ageing, NiAl particles nucleate rapidly with high number density and nearly reaches saturation, suppressing dislocation recovery. This leads to a high yield strength of 1875 MPa. When the ageing time is extended to 32 h, the NiAl particles coarsen and the volume fraction of M2C carbides increases, while the dislocation recovery remains minimal. Consequently, the yield strength increases slightly to 1895 MPa. Notably, the impact toughness improves from 17 J at 5 h to 28 J at 32 h, reflecting to a 65 % improvement. This is predominantly due to the reduction in the number density of brittle NiAl particles which can induce cracks and due to the formation of film-like reversed austenite which can deflect cracks. After 32 h of ageing, the yield strength and impact toughness of the secondary hardening steel are comparable to those of commercial AerMet310 steel. Notably, the cobalt content is reduced from 15.0 wt% to 5.0 wt%, resulting in an approximate 36 % reduction in raw material costs.
{"title":"Achieving ultra-high strength, good toughness and cost reduction in secondary hardening steel via dual precipitation","authors":"Haofei Zhu , Zhiping Xiong , Jianwen Mao , Xingwang Cheng","doi":"10.1016/j.matchar.2025.114869","DOIUrl":"10.1016/j.matchar.2025.114869","url":null,"abstract":"<div><div>The dual precipitation of NiAl particles and M<sub>2</sub>C carbides during ageing plays a critical role in achieving an optimal balance of strength and toughness in low-cobalt secondary hardening steel, yet this remains scarcely investigated. This work investigates the evolution of NiAl and M<sub>2</sub>C during ageing at 482 °C for durations ranging from 1 h to 150 h, focusing on their influence on the strength and impact toughness of martensitic steel. It was found that after 5 h of ageing, NiAl particles nucleate rapidly with high number density and nearly reaches saturation, suppressing dislocation recovery. This leads to a high yield strength of 1875 MPa. When the ageing time is extended to 32 h, the NiAl particles coarsen and the volume fraction of M<sub>2</sub>C carbides increases, while the dislocation recovery remains minimal. Consequently, the yield strength increases slightly to 1895 MPa. Notably, the impact toughness improves from 17 J at 5 h to 28 J at 32 h, reflecting to a 65 % improvement. This is predominantly due to the reduction in the number density of brittle NiAl particles which can induce cracks and due to the formation of film-like reversed austenite which can deflect cracks. After 32 h of ageing, the yield strength and impact toughness of the secondary hardening steel are comparable to those of commercial AerMet310 steel. Notably, the cobalt content is reduced from 15.0 wt% to 5.0 wt%, resulting in an approximate 36 % reduction in raw material costs.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"223 ","pages":"Article 114869"},"PeriodicalIF":4.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488827","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 : 2025-02-25DOI: 10.1016/j.matchar.2025.114881
Ming Ji , Hongguo Zhang , Weiqiang Liu , Xiangming Wang , Zhanjia Wang , Zizhen Guo , Haihui Wu , Ruihua Du , Shuhan Dong , Yuqing Li , Dongtao Zhang , Xiaofei Yi , Youhao Liu , Shanshun Zha , Ming Yue
The structure and phase modification of sintered Nd-Fe-B magnets through Tb diffusion from two different sources, nano TbHx and TbF3 particles, and their effects on magnetic and corrosion-resistant properties, were investigated. The results demonstrate that Tb diffusion from TbHx leads to an optimized microstructure with fewer anti-core-shell grains, a longer diffusion distance, and better magnetic isolation than TbF3. In contrast, TbF3 facilitates Tb diffusion into the main phase and also blocks its diffusion channels in the grain boundaries, resulting in accumulation at the surface and significantly reducing the diffusion efficiency of the Tb element. Additionally, the study reveals a key role of Tb in influencing the electrode potential of different phases and, consequently, the corrosion behavior of Nd-Fe-B magnets. Tb diffusion slightly increases the electrode potential of the shell of main phase grains while significantly increasing that of the NdO phase. It thus reduces the interphase potential difference thereby enhancing the corrosion resistance of the magnets. However, when TbF3 is used for diffusion, the formation of a new (Nd, Tb)-O-F phase, which exhibits significantly lower potential than the (Nd, Tb)-O phase, leads to a deterioration in corrosion resistance. These findings provide valuable insights into the magnetic and corrosion behaviors of grain boundary diffusion magnets and highlight key factors for developing advanced permanent magnets with enhanced overall performance.
{"title":"Strengthening magnetic and corrosion performances of NdFeB magnets via grain boundary diffusion with Tb element","authors":"Ming Ji , Hongguo Zhang , Weiqiang Liu , Xiangming Wang , Zhanjia Wang , Zizhen Guo , Haihui Wu , Ruihua Du , Shuhan Dong , Yuqing Li , Dongtao Zhang , Xiaofei Yi , Youhao Liu , Shanshun Zha , Ming Yue","doi":"10.1016/j.matchar.2025.114881","DOIUrl":"10.1016/j.matchar.2025.114881","url":null,"abstract":"<div><div>The structure and phase modification of sintered Nd-Fe-B magnets through Tb diffusion from two different sources, nano TbH<sub>x</sub> and TbF<sub>3</sub> particles, and their effects on magnetic and corrosion-resistant properties, were investigated. The results demonstrate that Tb diffusion from TbH<sub>x</sub> leads to an optimized microstructure with fewer anti-core-shell grains, a longer diffusion distance, and better magnetic isolation than TbF<sub>3</sub>. In contrast, TbF<sub>3</sub> facilitates Tb diffusion into the main phase and also blocks its diffusion channels in the grain boundaries, resulting in accumulation at the surface and significantly reducing the diffusion efficiency of the Tb element. Additionally, the study reveals a key role of Tb in influencing the electrode potential of different phases and, consequently, the corrosion behavior of Nd-Fe-B magnets. Tb diffusion slightly increases the electrode potential of the shell of main phase grains while significantly increasing that of the Nd<img>O phase. It thus reduces the interphase potential difference thereby enhancing the corrosion resistance of the magnets. However, when TbF<sub>3</sub> is used for diffusion, the formation of a new (Nd, Tb)-O-F phase, which exhibits significantly lower potential than the (Nd, Tb)-O phase, leads to a deterioration in corrosion resistance. These findings provide valuable insights into the magnetic and corrosion behaviors of grain boundary diffusion magnets and highlight key factors for developing advanced permanent magnets with enhanced overall performance.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"223 ","pages":"Article 114881"},"PeriodicalIF":4.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512593","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}
Fluorine-based compounds are indispensable in semiconductor manufacturing, nuclear technology, and aerospace industries, yet developing alloys resistant to fluorine-induced corrosion remains challenging. This study investigates the corrosion behavior of a Ni30Co30Cr30Mo10 medium-entropy alloy (MEA) in hydrofluoric acid (HF) solutions. The alloy, rapidly solidified via centrifugal casting, featured a primary γ phase (Ni- and Co-rich) with a highly refined dendritic microstructure, alongside a Cr- and Mo-rich σ phase uniformly distributed within the interdendritic regions. Immersion tests conducted over 28 days yielded average corrosion rates of 0.077, 0.202, and 0.134 mm/year in 20, 30, and 40 vol% HF solutions, respectively. Microstructural analysis revealed sub-100 nm Ni- and Co-rich corrosion products dispersed across the matrix surface. While a strongly adherent Cr-rich passive film formed on the σ phase, the γ phase developed a loosely structured Co-rich film. Although the corrosion appeared uniform at the macroscopic scale, the primary degradation mechanism was attributed to micro-galvanic interactions between the compositionally distinct γ and σ phases. These results advance our understanding of NiCoCrMo MEAs' corrosion behavior in HF environments and contribute to the development of improved fluorine-resistant alloys for advanced industrial applications.
{"title":"Microstructural evolution of NiCoCrMo medium-entropy alloy and its corrosion resistance in hydrofluoric acid","authors":"Zhutao Zhang , Hongqiang Fan , Jianlei Zhang , Changsheng Zhai , Hongxing Zheng","doi":"10.1016/j.matchar.2025.114876","DOIUrl":"10.1016/j.matchar.2025.114876","url":null,"abstract":"<div><div>Fluorine-based compounds are indispensable in semiconductor manufacturing, nuclear technology, and aerospace industries, yet developing alloys resistant to fluorine-induced corrosion remains challenging. This study investigates the corrosion behavior of a Ni<sub>30</sub>Co<sub>30</sub>Cr<sub>30</sub>Mo<sub>10</sub> medium-entropy alloy (MEA) in hydrofluoric acid (HF) solutions. The alloy, rapidly solidified <em>via</em> centrifugal casting, featured a primary <em>γ</em> phase (Ni- and Co-rich) with a highly refined dendritic microstructure, alongside a Cr- and Mo-rich <em>σ</em> phase uniformly distributed within the interdendritic regions. Immersion tests conducted over 28 days yielded average corrosion rates of 0.077, 0.202, and 0.134 mm/year in 20, 30, and 40 vol% HF solutions, respectively. Microstructural analysis revealed sub-100 nm Ni- and Co-rich corrosion products dispersed across the matrix surface. While a strongly adherent Cr-rich passive film formed on the <em>σ</em> phase, the <em>γ</em> phase developed a loosely structured Co-rich film. Although the corrosion appeared uniform at the macroscopic scale, the primary degradation mechanism was attributed to micro-galvanic interactions between the compositionally distinct <em>γ</em> and <em>σ</em> phases. These results advance our understanding of NiCoCrMo MEAs' corrosion behavior in HF environments and contribute to the development of improved fluorine-resistant alloys for advanced industrial applications.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"223 ","pages":"Article 114876"},"PeriodicalIF":4.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512594","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 : 2025-02-25DOI: 10.1016/j.matchar.2025.114870
Yi Lu, Shengping Wen, Wu Wei, Xiaolan Wu, Kunyuan Gao, Hui Huang, Zuoren Nie
In this investigation, a Si-containing Al-Zn-Mg-Cu alloy with good thermal stability caused by metastable GPB-II phases was found. This metastable GPB-II phase will finally transform into the L phase at 175 °C. In comparison to the Si-free alloy that underwent peak aging at 175 °C, the tensile strength, yield strength and elongation of the alloy with the addition of 0.35 wt% Si exhibited an increase of 75 MPa (24.9 %), 88 MPa (37.8 %) and 3.1 % (41.8 %), respectively. Furthermore, the yield strength and microhardness of the alloy with a Si content exceeding 0.35 wt% exhibited minimal decline during over-aging at 175 °C for 96 h and 160 °C for 500 h. It was observed that the number density of the η and T phases at the peak aging state decreased, and the average size doubled when 0.2 wt% Si was added. And with further addition of Si, the η and T phases are no longer present within the alloy, with only the more stable, fine, and uniform GPB-II phase remaining. Transmission electron microscope (TEM) observations indicate that the average size of the GPB-II phase remains unchanged with prolonged aging at 175 °C, which provides a rationale for the alloy's well thermal stability. From the perspective of cluster formation, we put forth a three-stage growth model to explain the formation and evolution of the GPB-II core-shell structure. In comparison, the thermal stability of the GPB-II phase is markedly superior to that of the L phase, predominantly as a consequence of the influence of the Guinier–Preston–Bagaryatsky (GPB) zone (Cu or Zn segregate) growth in the periphery of the L phase.
{"title":"High thermal stability of Si-containing Al-Zn-Mg-Cu crossover alloy caused by metastable GPB-II phase","authors":"Yi Lu, Shengping Wen, Wu Wei, Xiaolan Wu, Kunyuan Gao, Hui Huang, Zuoren Nie","doi":"10.1016/j.matchar.2025.114870","DOIUrl":"10.1016/j.matchar.2025.114870","url":null,"abstract":"<div><div>In this investigation, a Si-containing Al-Zn-Mg-Cu alloy with good thermal stability caused by metastable GPB-II phases was found. This metastable GPB-II phase will finally transform into the L phase at 175 °C. In comparison to the Si-free alloy that underwent peak aging at 175 °C, the tensile strength, yield strength and elongation of the alloy with the addition of 0.35 wt% Si exhibited an increase of 75 MPa (24.9 %), 88 MPa (37.8 %) and 3.1 % (41.8 %), respectively. Furthermore, the yield strength and microhardness of the alloy with a Si content exceeding 0.35 wt% exhibited minimal decline during over-aging at 175 °C for 96 h and 160 °C for 500 h. It was observed that the number density of the η and T phases at the peak aging state decreased, and the average size doubled when 0.2 wt% Si was added. And with further addition of Si, the η and T phases are no longer present within the alloy, with only the more stable, fine, and uniform GPB-II phase remaining. Transmission electron microscope (TEM) observations indicate that the average size of the GPB-II phase remains unchanged with prolonged aging at 175 °C, which provides a rationale for the alloy's well thermal stability. From the perspective of cluster formation, we put forth a three-stage growth model to explain the formation and evolution of the GPB-II core-shell structure. In comparison, the thermal stability of the GPB-II phase is markedly superior to that of the L phase, predominantly as a consequence of the influence of the Guinier–Preston–Bagaryatsky (GPB) zone (Cu or Zn segregate) growth in the periphery of the L phase.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"223 ","pages":"Article 114870"},"PeriodicalIF":4.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509165","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 : 2025-02-25DOI: 10.1016/j.matchar.2025.114875
Shijie Li , Chuanzhen Huang , Hanlian Liu , Zhenyu Shi , Lianggang Ji , Xinyao Cui , Chongzhen Du , Zhen Wang , Longhua Xu , Shuiquan Huang
To improve the properties of ceramic cutting tools, bionic ceramic cutting tools with innovative interfacial weaves in linear, triangular, square, and wavy shapes were fabricated by bionic design and the bottom-up assembly method. The stress distribution characteristics of the innovative interfacial textures were analyzed by finite element simulation. The effects of stress distribution in the innovative interfacial texture on the crack propagation mechanism were systematically investigated by crack propagation tests and double-sided shear tests, revealing their contribution to fracture resistance. Finally, the effect of residual stress on the properties and interfacial strengthening mechanism of the bionic ceramic cutting tool was evaluated with the microstructure evolution under the modulation of the innovative interfacial texture. The results show that the residual stress can generate a discontinuous stress concentration effect in the peak and valley regions of the innovative interfacial texture. The crack propagation and toughening mechanism can be modulated through stress concentration effects. The interfacial strengthening mechanism indicates that the appropriate and innovative interfacial textures can significantly enhance the mechanical properties and interfacial bonding strength, and further improve the fracture resistance and stability. Furthermore, the formed transition areas can modulate the residual stress distribution and enhance the interfacial bonding strength. The interfacial bonding strengths of linear, triangular, square, and wavy bionic ceramic cutting tools were 63.13 ± 6.4 MPa, 53.25 ± 4.3 MPa, 73.89 ± 8.0 MPa, and 93.26 ± 3.9 MPa, respectively. The wavy bionic ceramic tool exhibits optimal properties in terms of fracture toughness, Vickers hardness, and flexural strength, with values of 7.28 ± 0.27 MPa·m1/2, 21.53 ± 0.21 GPa, and 912.81 ± 40 MPa, respectively. This work can provide new ideas and methods to improve the properties of bionic ceramic cutting tools.
{"title":"FEM and experimental research on residual stress, crack propagation and toughening mechanisms of novel bionic ceramic cutting tools","authors":"Shijie Li , Chuanzhen Huang , Hanlian Liu , Zhenyu Shi , Lianggang Ji , Xinyao Cui , Chongzhen Du , Zhen Wang , Longhua Xu , Shuiquan Huang","doi":"10.1016/j.matchar.2025.114875","DOIUrl":"10.1016/j.matchar.2025.114875","url":null,"abstract":"<div><div>To improve the properties of ceramic cutting tools, bionic ceramic cutting tools with innovative interfacial weaves in linear, triangular, square, and wavy shapes were fabricated by bionic design and the bottom-up assembly method. The stress distribution characteristics of the innovative interfacial textures were analyzed by finite element simulation. The effects of stress distribution in the innovative interfacial texture on the crack propagation mechanism were systematically investigated by crack propagation tests and double-sided shear tests, revealing their contribution to fracture resistance. Finally, the effect of residual stress on the properties and interfacial strengthening mechanism of the bionic ceramic cutting tool was evaluated with the microstructure evolution under the modulation of the innovative interfacial texture. The results show that the residual stress can generate a discontinuous stress concentration effect in the peak and valley regions of the innovative interfacial texture. The crack propagation and toughening mechanism can be modulated through stress concentration effects. The interfacial strengthening mechanism indicates that the appropriate and innovative interfacial textures can significantly enhance the mechanical properties and interfacial bonding strength, and further improve the fracture resistance and stability. Furthermore, the formed transition areas can modulate the residual stress distribution and enhance the interfacial bonding strength. The interfacial bonding strengths of linear, triangular, square, and wavy bionic ceramic cutting tools were 63.13 ± 6.4 MPa, 53.25 ± 4.3 MPa, 73.89 ± 8.0 MPa, and 93.26 ± 3.9 MPa, respectively. The wavy bionic ceramic tool exhibits optimal properties in terms of fracture toughness, Vickers hardness, and flexural strength, with values of 7.28 ± 0.27 MPa·m<sup>1/2</sup>, 21.53 ± 0.21 GPa, and 912.81 ± 40 MPa, respectively. This work can provide new ideas and methods to improve the properties of bionic ceramic cutting tools.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"223 ","pages":"Article 114875"},"PeriodicalIF":4.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512597","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 : 2025-02-25DOI: 10.1016/j.matchar.2025.114878
A.R. Richter , F. Scholz , G. Eggeler , J. Frenzel , P. Thome
Microstructure informatics, an emerging field, combines traditional quantitative metallography with computer vision, algorithmic geometry and data science. It uses automated procedures to retrieve statistically relevant information from micrographs. Its power is demonstrated in a case study which focusses on competitive dendrite growth during directional solidification of single crystal Ni-base superalloys (SXs) in 3D. We show how microstructure informatics allows to follow the evolution of all dendrites in a cylindric SX bar (diameter: 12 mm, analyzed length: 76 mm), evaluating serial cross sections taken in 1 mm distances. The method presented in this work relies on three basic components: (1) A deep learning object detection network for detecting dendrite core positions. (2) A 3D image reconstruction routine for tracing dendrite paths and (3) a relational geometric ontological (RGO) database, documenting all relevant relationships between individual dendrites. The method allows to characterize crystal mosaicity, individual dendrite growth directions, interactions between dendrites and dendrite deformation. The performance of different deep learning classification architectures (AlexNet, GoogleNet and MobileNetV2) in combination with a YOLOv2 subdetection network is investigated. The network hyper parameters were optimized to achieve detection rates >99 %. A resulting ontological database of 16,631 individual dendrites provides a foundation for further automatic quantitative microstructural characterization.
{"title":"Microstructure informatics: Using computer vision for the characterization of dendrite growth phenomena in Ni-base single crystal Superalloys","authors":"A.R. Richter , F. Scholz , G. Eggeler , J. Frenzel , P. Thome","doi":"10.1016/j.matchar.2025.114878","DOIUrl":"10.1016/j.matchar.2025.114878","url":null,"abstract":"<div><div>Microstructure informatics, an emerging field, combines traditional quantitative metallography with computer vision, algorithmic geometry and data science. It uses automated procedures to retrieve statistically relevant information from micrographs. Its power is demonstrated in a case study which focusses on competitive dendrite growth during directional solidification of single crystal Ni-base superalloys (SXs) in 3D. We show how microstructure informatics allows to follow the evolution of all dendrites in a cylindric SX bar (diameter: 12 mm, analyzed length: 76 mm), evaluating serial cross sections taken in 1 mm distances. The method presented in this work relies on three basic components: (1) A deep learning object detection network for detecting dendrite core positions. (2) A 3D image reconstruction routine for tracing dendrite paths and (3) a relational geometric ontological (RGO) database, documenting all relevant relationships between individual dendrites. The method allows to characterize crystal mosaicity, individual dendrite growth directions, interactions between dendrites and dendrite deformation. The performance of different deep learning classification architectures (AlexNet, GoogleNet and MobileNetV2) in combination with a YOLOv2 subdetection network is investigated. The network hyper parameters were optimized to achieve detection rates >99 %. A resulting ontological database of 16,631 individual dendrites provides a foundation for further automatic quantitative microstructural characterization.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"223 ","pages":"Article 114878"},"PeriodicalIF":4.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vacuum hot-compression bonding (VHCB) has emerged as a promising method for fabricating critical structural components, offering a viable alternative to traditional heavy forging manufacturing. To verify the feasibility and applicability of VHCB in aluminum alloys, a comprehensive study was conducted on the interfacial bonding behavior of 2219 aluminum alloy joints at various temperatures and holding times. The strengthening-failure mechanism of the joints was explored. The results showed that increasing the bonding temperature and holding time enhanced the interfacial bonding quality by promoting void closure, interfacial grain boundary migration (IGBM), and dissolution of interfacial oxides. The joint bonded at 540 °C-30 %-6 h achieved metallurgical bonding by IGBM and dynamic recrystallization (DRX). The initial straight interface was occupied by interfacial fine grains and bulged grain boundaries. The interfacial oxides were transformed into the MgAl2O4 phase. Both dislocation strengthening and the interface strengthening collaboratively promoted the strong bonding of the joint. Tensile results indicated that the joint exhibited a yield strength of 127.4 MPa and an ultimate tensile strength of 246.3 MPa, reflecting increases of 31.9 MPa and 39.4 MPa compared to the base material. The joint cracked at a distance of about 300 μm from the bonding interface, and the crack exhibited a wavy fracture along the interface. These findings provide practical guidelines for applying VHCB technology in the fabrication of 2219 aluminum alloy components.
{"title":"Interface bonding behavior and strengthening-failure analysis of 2219 aluminum alloy joint produced by vacuum hot-compression bonding","authors":"Dazhao Xu , Linggang Meng , Jinkai Wu , Yunfeng Liu , Xingguo Zhang","doi":"10.1016/j.matchar.2025.114871","DOIUrl":"10.1016/j.matchar.2025.114871","url":null,"abstract":"<div><div>Vacuum hot-compression bonding (VHCB) has emerged as a promising method for fabricating critical structural components, offering a viable alternative to traditional heavy forging manufacturing. To verify the feasibility and applicability of VHCB in aluminum alloys, a comprehensive study was conducted on the interfacial bonding behavior of 2219 aluminum alloy joints at various temperatures and holding times. The strengthening-failure mechanism of the joints was explored. The results showed that increasing the bonding temperature and holding time enhanced the interfacial bonding quality by promoting void closure, interfacial grain boundary migration (IGBM), and dissolution of interfacial oxides. The joint bonded at 540 °C-30 %-6 h achieved metallurgical bonding by IGBM and dynamic recrystallization (DRX). The initial straight interface was occupied by interfacial fine grains and bulged grain boundaries. The interfacial oxides were transformed into the MgAl<sub>2</sub>O<sub>4</sub> phase. Both dislocation strengthening and the interface strengthening collaboratively promoted the strong bonding of the joint. Tensile results indicated that the joint exhibited a yield strength of 127.4 MPa and an ultimate tensile strength of 246.3 MPa, reflecting increases of 31.9 MPa and 39.4 MPa compared to the base material. The joint cracked at a distance of about 300 μm from the bonding interface, and the crack exhibited a wavy fracture along the interface. These findings provide practical guidelines for applying VHCB technology in the fabrication of 2219 aluminum alloy components.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"222 ","pages":"Article 114871"},"PeriodicalIF":4.8,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487249","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 : 2025-02-24DOI: 10.1016/j.matchar.2025.114874
Ding Zhao , Jiangkun Fan , Zhixin Zhang , Xiaoyuan Liang , Zesen Chen , Zhiyong Chen , Minjie Lai , Bin Tang , Hongchao Kou , Qingjiang Wang , Jinshan Li
The elucidation of the impact of the initial texture and cooling rate on the variant selection (VS) mechanism of α-phase in titanium alloys is essential for optimising their microstructure and mechanical properties. In this study, Ti65 foils featuring three different initial textures underwent annealing in the α + β phase region, followed by cooling at three different rates. Under slow cooling conditions (furnace cooling), the primary mechanism governing texture evolution of α-phase is the grain growth of the primary α (αp) grains. Consequently, the effect of the initial texture on the texture evolution of α-phase under slow cooling is ascribed to variations in the αp grains in the samples after heat treatments. Additionally, standard disorientation angle θm distribution maps of the α texture under different β textures are developed to predict the texture of the αp grains. In contrast, during rapid cooling (200 °C/min cooling and air cooling), texture evolution of α-phase is driven by the precipitation of the secondary α (αs) grains. In this case, a change in the cooling rate has no effect on the VS mechanism of α-phase at the αp/β and β/β boundaries, but it changes the VS mechanism of α-phase at the parent β grain interior. Therefore, the influence of the initial texture on VS mechanism of α-phase under rapid cooling varies with cooling rates, depending on the ratio of αs grains precipitated at αp/β and β/β boundaries to the αs grains precipitated at the parent β grain interior.
{"title":"Variant selection mechanism of α phase associated with initial texture and cooling rate in near-α titanium alloy Ti65","authors":"Ding Zhao , Jiangkun Fan , Zhixin Zhang , Xiaoyuan Liang , Zesen Chen , Zhiyong Chen , Minjie Lai , Bin Tang , Hongchao Kou , Qingjiang Wang , Jinshan Li","doi":"10.1016/j.matchar.2025.114874","DOIUrl":"10.1016/j.matchar.2025.114874","url":null,"abstract":"<div><div>The elucidation of the impact of the initial texture and cooling rate on the variant selection (VS) mechanism of α-phase in titanium alloys is essential for optimising their microstructure and mechanical properties. In this study, Ti65 foils featuring three different initial textures underwent annealing in the α + β phase region, followed by cooling at three different rates. Under slow cooling conditions (furnace cooling), the primary mechanism governing texture evolution of α-phase is the grain growth of the primary α (α<sub>p</sub>) grains. Consequently, the effect of the initial texture on the texture evolution of α-phase under slow cooling is ascribed to variations in the α<sub>p</sub> grains in the samples after heat treatments. Additionally, standard disorientation angle <strong><em>θ</em></strong><sub><strong><em>m</em></strong></sub> distribution maps of the α texture under different β textures are developed to predict the texture of the α<sub>p</sub> grains. In contrast, during rapid cooling (200 °C/min cooling and air cooling), texture evolution of α-phase is driven by the precipitation of the secondary α (α<sub>s</sub>) grains. In this case, a change in the cooling rate has no effect on the VS mechanism of α-phase at the α<sub>p</sub>/β and β/β boundaries, but it changes the VS mechanism of α-phase at the parent β grain interior. Therefore, the influence of the initial texture on VS mechanism of α-phase under rapid cooling varies with cooling rates, depending on the ratio of α<sub>s</sub> grains precipitated at α<sub>p</sub>/β and β/β boundaries to the α<sub>s</sub> grains precipitated at the parent β grain interior.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"223 ","pages":"Article 114874"},"PeriodicalIF":4.8,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509163","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 : 2025-02-24DOI: 10.1016/j.matchar.2025.114873
Xiali Zhen , Lu Li , Ruixiao Zheng , Chaoli Ma
Due to the significance of interphases for SiCf/SiC composites, interfacial characterization is an indispensable task and tool for composites manufacturing. In this work, optimized fiber push-out, fiber push-in and micropillar compression were used to measure the interfacial properties and analyze the interfacial debonding process. To accurately acquire the interfacial properties, improve the measurement result reliability and evaluate the method applicability, the detailed test procedures and parameters of different techniques were investigated and reformed. In addition, for the first time, a novel debonding-slipping micropillar compression combined with in-situ observation was designed and applied to separate the debonding and slipping stages and calculate the interfacial debonding energy. The interfacial failure process and energy dissipation mechanism of SiCf/SiC composites were clarified. Coupled with the morphology characterization, the optimized interfacial evaluation methods have provided a further understanding of mechanical response curves and parameters, as well as the debonding failure process of interface, while also providing essential data support for the interphase design of high-performance ceramic matrix composites.
{"title":"Optimized interfacial evaluation methods of SiCf/SiC composites: fiber push-out, fiber push-in and micropillar compression","authors":"Xiali Zhen , Lu Li , Ruixiao Zheng , Chaoli Ma","doi":"10.1016/j.matchar.2025.114873","DOIUrl":"10.1016/j.matchar.2025.114873","url":null,"abstract":"<div><div>Due to the significance of interphases for SiC<sub>f</sub>/SiC composites, interfacial characterization is an indispensable task and tool for composites manufacturing. In this work, optimized fiber push-out, fiber push-in and micropillar compression were used to measure the interfacial properties and analyze the interfacial debonding process. To accurately acquire the interfacial properties, improve the measurement result reliability and evaluate the method applicability, the detailed test procedures and parameters of different techniques were investigated and reformed. In addition, for the first time, a novel debonding-slipping micropillar compression combined with in-situ observation was designed and applied to separate the debonding and slipping stages and calculate the interfacial debonding energy. The interfacial failure process and energy dissipation mechanism of SiC<sub>f</sub>/SiC composites were clarified. Coupled with the morphology characterization, the optimized interfacial evaluation methods have provided a further understanding of mechanical response curves and parameters, as well as the debonding failure process of interface, while also providing essential data support for the interphase design of high-performance ceramic matrix composites.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"223 ","pages":"Article 114873"},"PeriodicalIF":4.8,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509164","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 : 2025-02-22DOI: 10.1016/j.matchar.2025.114868
W.P. Tian, Z.Y. Zhang, Z.Q. Jin, G.M. Xie
Wire-arc direct energy deposition (DED) holds significant potential for fabricating and repairing large-scale steel structures. However, the process faces substantial challenges, particularly for high-alloy steels like martensitic stainless steel. Complex thermal cycling and uneven heat dissipation frequently result in heterogeneous microstructures and compromised mechanical properties. These issues are further exacerbated by the inherent difficulties of applying conventional post-treatments that are cost-prohibitive and infeasible for large or geometrically intricate components. This study presents an assisted pre-heating and slow-cooling (H-SC) strategy, supported by 3D finite-element modeling to investigate the dynamic thermal behaviors and microstructural evolution, to address microstructural inhomogeneity and enable high-quality wire-arc DED manufacturing without post-treatment. Thin-wall super martensitic stainless steel parts were fabricated with and without this strategy. The H-SC sample exhibited columnar lath martensite grains with nano inclusions, while the sample without the H-SC strategy showed alternating columnar and equiaxed grains with micron inclusions. The synergy of microstructural homogeneity, nano inclusions, and continuous columnar grains significantly enhanced the properties of as-deposited parts. The H-SC strategy minimized anisotropy and position-related non-uniformity in mechanical properties. Additionally, it improved the longitudinal tensile strength by 24 % (up to 1185 MPa) and elongation by 16 % (up to 16.4 %), achieving properties comparable to quenched specimens. This research underscores the importance of thermal management in wire-arc DED for tailoring microstructures and optimizing performance, providing valuable insights for advancing additive manufacturing and repairing in industrial applications.
{"title":"Influence of substrate pre-heating on microstructural homogeneity in wire-arc additively manufactured super martensitic stainless steel","authors":"W.P. Tian, Z.Y. Zhang, Z.Q. Jin, G.M. Xie","doi":"10.1016/j.matchar.2025.114868","DOIUrl":"10.1016/j.matchar.2025.114868","url":null,"abstract":"<div><div>Wire-arc direct energy deposition (DED) holds significant potential for fabricating and repairing large-scale steel structures. However, the process faces substantial challenges, particularly for high-alloy steels like martensitic stainless steel. Complex thermal cycling and uneven heat dissipation frequently result in heterogeneous microstructures and compromised mechanical properties. These issues are further exacerbated by the inherent difficulties of applying conventional post-treatments that are cost-prohibitive and infeasible for large or geometrically intricate components. This study presents an assisted pre-heating and slow-cooling (H-SC) strategy, supported by 3D finite-element modeling to investigate the dynamic thermal behaviors and microstructural evolution, to address microstructural inhomogeneity and enable high-quality wire-arc DED manufacturing without post-treatment. Thin-wall super martensitic stainless steel parts were fabricated with and without this strategy. The H-SC sample exhibited columnar lath martensite grains with nano inclusions, while the sample without the H-SC strategy showed alternating columnar and equiaxed grains with micron inclusions. The synergy of microstructural homogeneity, nano inclusions, and continuous columnar grains significantly enhanced the properties of as-deposited parts. The H-SC strategy minimized anisotropy and position-related non-uniformity in mechanical properties. Additionally, it improved the longitudinal tensile strength by 24 % (up to 1185 MPa) and elongation by 16 % (up to 16.4 %), achieving properties comparable to quenched specimens. This research underscores the importance of thermal management in wire-arc DED for tailoring microstructures and optimizing performance, providing valuable insights for advancing additive manufacturing and repairing in industrial applications.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"222 ","pages":"Article 114868"},"PeriodicalIF":4.8,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487251","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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