Pub Date : 2025-02-21DOI: 10.1016/j.matchar.2025.114867
Sandra Puchlerska , Henryk Paul , Seyed Mahmood Fatemi , Robert Chulist , Mariusz Prażmowski
The study addresses the formation of shear bands in polycrystalline titanium subjected to dynamic deformation at room temperature. Hat-shaped samples were cut from a hot-extruded rod, both along and perpendicular to the extrusion direction, and then deformed at a strain rate of 4.9 × 103 s−1 using a drop hammer. Structural and textural analyses were performed on the axial sections of the samples using a scanning electron microscope equipped with an electron backscatter diffraction device. Regardless of the initial texture of the samples, a pronounced, oriented rotation of the crystal lattice was observed in grains located within the strain localization region. The primary rotation trend oriented the {0001} planes perpendicular to the shear plane and parallel to the loading direction, with one of the {1−100} planes aligned parallel to the shear plane, whereas a 〈11−20〉 direction, common to both planes, was aligned parallel to the shear direction. This crystal lattice rotation mechanism observed in grains of the strain localization region facilitates slip propagation across grain boundaries without an apparent change in the shear direction.
{"title":"Crystal lattice rotations during shear band formation in pure titanium deformed at high strain rate","authors":"Sandra Puchlerska , Henryk Paul , Seyed Mahmood Fatemi , Robert Chulist , Mariusz Prażmowski","doi":"10.1016/j.matchar.2025.114867","DOIUrl":"10.1016/j.matchar.2025.114867","url":null,"abstract":"<div><div>The study addresses the formation of shear bands in polycrystalline titanium subjected to dynamic deformation at room temperature. Hat-shaped samples were cut from a hot-extruded rod, both along and perpendicular to the extrusion direction, and then deformed at a strain rate of 4.9 × 10<sup>3</sup> s<sup>−1</sup> using a drop hammer. Structural and textural analyses were performed on the axial sections of the samples using a scanning electron microscope equipped with an electron backscatter diffraction device. Regardless of the initial texture of the samples, a pronounced, oriented rotation of the crystal lattice was observed in grains located within the strain localization region. The primary rotation trend oriented the {0001} planes perpendicular to the shear plane and parallel to the loading direction, with one of the {1−100} planes aligned parallel to the shear plane, whereas a 〈11−20〉 direction, common to both planes, was aligned parallel to the shear direction. This crystal lattice rotation mechanism observed in grains of the strain localization region facilitates slip propagation across grain boundaries without an apparent change in the shear direction.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"222 ","pages":"Article 114867"},"PeriodicalIF":4.8,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479892","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}
Pub Date : 2025-02-21DOI: 10.1016/j.matchar.2025.114866
Yiping Yu, Hao Li, Bing Fang, Wei Li, Song Wang
Environmental barrier coating (EBC) is of great important for silicon carbide-based ceramic matrix composites (SiC-CMCs) applied in aero-engine. However, conventional EBC materials like silicates have insufficient corrosion resistance to water vapor and molten salt in extremely harsh environments of aero-engine. We herein develop a novel EBC material of AlHfTaO6. It not only shows a strong resistance to high temperature water vapor and molten salt corrosion, but also has a low thermal conductivity of 1.4–1.8 W·m−1·K−1 from room temperature to 1500 °C. Additionally, the thermal expansion coefficient of AlHfTaO6 (5 × 10−6–8 × 10−6 K−1) closely matches that of SiC-CMCs (4 × 10−6–6 × 10−6 K−1), suggesting excellent compatibility and integration during service. These results demonstrate that AlHfTaO6 is a promising environmental barrier coating material, and may have great benefits for improving working temperature and service life of SiC-CMCs in aero-engine.
{"title":"A novel environmental barrier coating material of AlHfTaO6 with low thermal conductivity and high corrosion resistance","authors":"Yiping Yu, Hao Li, Bing Fang, Wei Li, Song Wang","doi":"10.1016/j.matchar.2025.114866","DOIUrl":"10.1016/j.matchar.2025.114866","url":null,"abstract":"<div><div>Environmental barrier coating (EBC) is of great important for silicon carbide-based ceramic matrix composites (SiC-CMCs) applied in aero-engine. However, conventional EBC materials like silicates have insufficient corrosion resistance to water vapor and molten salt in extremely harsh environments of aero-engine. We herein develop a novel EBC material of AlHfTaO<sub>6</sub>. It not only shows a strong resistance to high temperature water vapor and molten salt corrosion, but also has a low thermal conductivity of 1.4–1.8 W·m<sup>−1</sup>·K<sup>−1</sup> from room temperature to 1500 °C. Additionally, the thermal expansion coefficient of AlHfTaO<sub>6</sub> (5 × 10<sup>−6</sup>–8 × 10<sup>−6</sup> K<sup>−1</sup>) closely matches that of SiC-CMCs (4 × 10<sup>−6</sup>–6 × 10<sup>−6</sup> K<sup>−1</sup>), suggesting excellent compatibility and integration during service. These results demonstrate that AlHfTaO<sub>6</sub> is a promising environmental barrier coating material, and may have great benefits for improving working temperature and service life of SiC-CMCs in aero-engine.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"223 ","pages":"Article 114866"},"PeriodicalIF":4.8,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512596","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 : 2025-02-20DOI: 10.1016/j.matchar.2025.114863
Haoze Wu , Yunpeng Wang , Qinglin Ma , Yu Wang , Zhimin Li
As a typical representative of ancient southern Chinese folk kilns, the Qiong kiln, the firing process, and the corrosion behavior of its opaque glaze celadon are of great significance in revealing the deterioration mechanism of Indigenous ceramic materials. In this study, eight pieces of Tang dynasty opaque glaze celadon excavated from the Qiong kiln's Shifangtang kiln site were taken as the research object, and the glaze corrosion morphology and mechanism under the synergistic effect of glaze corrosion characteristics, physical composition and burial environment were systematically investigated by means of the super depth-of-field microscope, scanning electron microscope-energy spectroscopy (SEM-EDS), Raman spectroscopy, and optical coherence tomography (OCT) techniques. The results show that the corrosion behavior of the glaze layer is significantly affected by the composition of raw materials and the firing process: the incompletely fused quartz particles and precipitated augite crystals become the preferred corrosion sites due to the difference in chemical stability at the interface with the glass phase, which leads to the dislodgement of the crystals and the formation of honeycomb-shaped corrosion pits. The geometrical characteristics of the corrosion pits (increased specific surface area compared to the original glaze) accelerated the interfacial ion-exchange reactions while providing deposition channels for inorganic colloids from the environment to form hollow spherical silicate crusts. This study reveals the multi-scale synergistic corrosion mechanism of the crystal phase - bubble pits - iron deposition material in Qiong kiln opaque glaze celadon, which provides a scientific basis for the development of a targeted cultural relics protection strategy.
{"title":"Corrosion studies on Tang dynasty opaque glaze celadon excavated from Qiong kiln, Sichuan, China","authors":"Haoze Wu , Yunpeng Wang , Qinglin Ma , Yu Wang , Zhimin Li","doi":"10.1016/j.matchar.2025.114863","DOIUrl":"10.1016/j.matchar.2025.114863","url":null,"abstract":"<div><div>As a typical representative of ancient southern Chinese folk kilns, the Qiong kiln, the firing process, and the corrosion behavior of its opaque glaze celadon are of great significance in revealing the deterioration mechanism of Indigenous ceramic materials. In this study, eight pieces of Tang dynasty opaque glaze celadon excavated from the Qiong kiln's Shifangtang kiln site were taken as the research object, and the glaze corrosion morphology and mechanism under the synergistic effect of glaze corrosion characteristics, physical composition and burial environment were systematically investigated by means of the super depth-of-field microscope, scanning electron microscope-energy spectroscopy (SEM-EDS), Raman spectroscopy, and optical coherence tomography (OCT) techniques. The results show that the corrosion behavior of the glaze layer is significantly affected by the composition of raw materials and the firing process: the incompletely fused quartz particles and precipitated augite crystals become the preferred corrosion sites due to the difference in chemical stability at the interface with the glass phase, which leads to the dislodgement of the crystals and the formation of honeycomb-shaped corrosion pits. The geometrical characteristics of the corrosion pits (increased specific surface area compared to the original glaze) accelerated the interfacial ion-exchange reactions while providing deposition channels for inorganic colloids from the environment to form hollow spherical silicate crusts. This study reveals the multi-scale synergistic corrosion mechanism of the crystal phase - bubble pits - iron deposition material in Qiong kiln opaque glaze celadon, which provides a scientific basis for the development of a targeted cultural relics protection strategy.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"222 ","pages":"Article 114863"},"PeriodicalIF":4.8,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465554","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}
This study investigates the extruded texture of a 6xxx series high-strength aluminium alloy as a function of profile geometry using Electron Backscatter Diffraction (EBSD) and X-Ray diffraction pattern (XRD). A novel texture analysis method was designed to acquire and prepare reliable texture data for machine learning applications. The method categorizes textures into five distinct groups, with volume fractions calculated for each group. Furthermore, finite element analysis of the extrusion process revealed that axial tensile strain promotes a combination of 〈100〉 and 〈111〉 //ED texture components, while shear deformation induces 〈211〉 //ED texture components. The results were subsequently fed into an artificial neural network (ANN) model developed to link the texture to profile geometry, which governs the deformation modes experienced during the material flow. This approach represents a significant advancement towards real-time control of material properties during extrusion.
{"title":"Novel texture analysis method for optimising material property in extruded 6xxx alloys using artificial neural networks","authors":"Mian Zhou , Chrysoula Tzileroglou , Carla Barbatti , Hamid Assadi","doi":"10.1016/j.matchar.2025.114859","DOIUrl":"10.1016/j.matchar.2025.114859","url":null,"abstract":"<div><div>This study investigates the extruded texture of a 6xxx series high-strength aluminium alloy as a function of profile geometry using Electron Backscatter Diffraction (EBSD) and X-Ray diffraction pattern (XRD). A novel texture analysis method was designed to acquire and prepare reliable texture data for machine learning applications. The method categorizes textures into five distinct groups, with volume fractions calculated for each group. Furthermore, finite element analysis of the extrusion process revealed that axial tensile strain promotes a combination of 〈100〉 and 〈111〉 //ED texture components, while shear deformation induces 〈211〉 //ED texture components. The results were subsequently fed into an artificial neural network (ANN) model developed to link the texture to profile geometry, which governs the deformation modes experienced during the material flow. This approach represents a significant advancement towards real-time control of material properties during extrusion.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"223 ","pages":"Article 114859"},"PeriodicalIF":4.8,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508735","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}
Pub Date : 2025-02-20DOI: 10.1016/j.matchar.2025.114864
Bo Du , Minglin He , Wenshen Tang , Xinqi Yang , Jiang Yi , Shuai Wang
Bonding interface is the weakest zone in defect-free friction plug weld (FPW) of 2219 aluminum alloy. To elucidate the specific fracture mechanism, the bonding interface of the FPW joint was precisely sampled and detailed characterized in this study. The bonding interface exhibit a heterogeneous microstructure along the thickness direction of FPW joint. In the middle part of the bonding interface, the recrystallization is the most adequate and the grain size is smallest, due to the largest interfacial normal force compared with the upper and lower parts. More importantly, a coarse θ-phase layer is identified along the bonding interface in the lower part of the FPW joint. These coarse θ phases are mainly formed by the accumulation and growth of original θ phases in the matrix, due to the inadequate interfacial normal force in the lower part. Cracks are easily formed and expanded along this coarse θ-phase layer, eventually leading to the low ultimate tensile strength and elongation of the defect-free FPW joint.
{"title":"Heterogeneity of interfacial microstructure and fracture behavior of friction plug welds for 2219-T87 AlCu alloy","authors":"Bo Du , Minglin He , Wenshen Tang , Xinqi Yang , Jiang Yi , Shuai Wang","doi":"10.1016/j.matchar.2025.114864","DOIUrl":"10.1016/j.matchar.2025.114864","url":null,"abstract":"<div><div>Bonding interface is the weakest zone in defect-free friction plug weld (FPW) of 2219 aluminum alloy. To elucidate the specific fracture mechanism, the bonding interface of the FPW joint was precisely sampled and detailed characterized in this study. The bonding interface exhibit a heterogeneous microstructure along the thickness direction of FPW joint. In the middle part of the bonding interface, the recrystallization is the most adequate and the grain size is smallest, due to the largest interfacial normal force compared with the upper and lower parts. More importantly, a coarse θ-phase layer is identified along the bonding interface in the lower part of the FPW joint. These coarse θ phases are mainly formed by the accumulation and growth of original θ phases in the matrix, due to the inadequate interfacial normal force in the lower part. Cracks are easily formed and expanded along this coarse θ-phase layer, eventually leading to the low ultimate tensile strength and elongation of the defect-free FPW joint.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"222 ","pages":"Article 114864"},"PeriodicalIF":4.8,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479893","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 : 2025-02-20DOI: 10.1016/j.matchar.2025.114862
André A. Ferreira , Ana R. Reis , João P. Sousa , João M. Cruz , Manuel F. Vieira
The production of functional gradient materials (FGM) is an option for the various industrial sectors and a solution for many engineering applications. FGM's are a class of materials that can also be characterised as metal composites that gradually change composition and structure. In this study, the production of FGM's on 42CrMo4 structural steel substrate, varying the composition from 100 % Inconel 625 to 100 % NiCrWMo alloy, was successfully fabricated using the Direct Laser Deposition technique. The substrate was pre-heated to decrease the cooling rate and the formation of metastable phases of the heat-affected zone, and for comparison purposes, deposition was performed on the substrate without pre-heating. A mixture of Inconel 625 and NiCrWMo-type nickel superalloy powders was used to produce functionally graded structures. Microstructural characterisation and phase identification were performed by scanning electron microscopy, chemical analyses by energy-dispersive x-ray spectroscopy and electron backscatter diffraction. Microhardness mapping performed on the FGMs allowed the hardness profile along the gradient to be evaluated and correlated with the chemical analyses to be performed. The metallurgical, chemical, and mechanical characterisations and the correlation with process parameters are determined and discussed throughout this investigation. This research shows an innovative FGM, which has not yet been produced, allowing this research to evaluate the characteristics of each powder's mixture composition. It was also possible to observe the effect of alloying elements on the microstructure and hardness of the graded materials.
{"title":"Inconel 625/NiCrWMo functionally graded materials manufactured by direct laser deposition","authors":"André A. Ferreira , Ana R. Reis , João P. Sousa , João M. Cruz , Manuel F. Vieira","doi":"10.1016/j.matchar.2025.114862","DOIUrl":"10.1016/j.matchar.2025.114862","url":null,"abstract":"<div><div>The production of functional gradient materials (FGM) is an option for the various industrial sectors and a solution for many engineering applications. FGM's are a class of materials that can also be characterised as metal composites that gradually change composition and structure. In this study, the production of FGM's on 42CrMo4 structural steel substrate, varying the composition from 100 % Inconel 625 to 100 % NiCrWMo alloy, was successfully fabricated using the Direct Laser Deposition technique. The substrate was pre-heated to decrease the cooling rate and the formation of metastable phases of the heat-affected zone, and for comparison purposes, deposition was performed on the substrate without pre-heating. A mixture of Inconel 625 and NiCrWMo-type nickel superalloy powders was used to produce functionally graded structures. Microstructural characterisation and phase identification were performed by scanning electron microscopy, chemical analyses by energy-dispersive x-ray spectroscopy and electron backscatter diffraction. Microhardness mapping performed on the FGMs allowed the hardness profile along the gradient to be evaluated and correlated with the chemical analyses to be performed. The metallurgical, chemical, and mechanical characterisations and the correlation with process parameters are determined and discussed throughout this investigation. This research shows an innovative FGM, which has not yet been produced, allowing this research to evaluate the characteristics of each powder's mixture composition. It was also possible to observe the effect of alloying elements on the microstructure and hardness of the graded materials.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"222 ","pages":"Article 114862"},"PeriodicalIF":4.8,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474577","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 : 2025-02-19DOI: 10.1016/j.matchar.2025.114841
Amit Singh , Mark Obstalecki , Darren C. Pagan , Michael Glavicic , Matthew Kasemer
Emerging microstructural characterization methods have received increased attention owing to their promise of relatively inexpensive and rapid measurement of polycrystalline surface morphology and crystallographic orientations. Among these nascent methods, polarized light microscopy (PLM) is attractive for characterizing alloys comprised of hexagonal crystals, but is hindered by its inability to measure complete crystal orientations. In this study, we explore the potential to reconstruct quasi-deterministic orientations for titanium microstructures characterized via PLM by considering the Burgers orientation relationship between the room temperature α (HCP) phase fibers measured via PLM, and the β (BCC) phase orientations of the parent grains present above the transus temperature. We describe this method—which is capable of narrowing down the orientations to one of four possibilities—and demonstrate its abilities on idealized computational samples in which the parent β microstructure is fully, unambiguously known. We further utilize this method to inform the instantiation of samples for crystal plasticity simulations, and demonstrate the significant improvement in deformation field predictions when utilizing this reconstruction method compared to using results from traditional PLM.
{"title":"Orientation reconstruction of transformation α titanium alloys via polarized light microscopy: Methodology and assessment","authors":"Amit Singh , Mark Obstalecki , Darren C. Pagan , Michael Glavicic , Matthew Kasemer","doi":"10.1016/j.matchar.2025.114841","DOIUrl":"10.1016/j.matchar.2025.114841","url":null,"abstract":"<div><div>Emerging microstructural characterization methods have received increased attention owing to their promise of relatively inexpensive and rapid measurement of polycrystalline surface morphology and crystallographic orientations. Among these nascent methods, polarized light microscopy (PLM) is attractive for characterizing alloys comprised of hexagonal crystals, but is hindered by its inability to measure complete crystal orientations. In this study, we explore the potential to reconstruct quasi-deterministic orientations for titanium microstructures characterized via PLM by considering the Burgers orientation relationship between the room temperature <em>α</em> (HCP) phase fibers measured via PLM, and the <em>β</em> (BCC) phase orientations of the parent grains present above the transus temperature. We describe this method—which is capable of narrowing down the orientations to one of four possibilities—and demonstrate its abilities on idealized computational samples in which the parent <em>β</em> microstructure is fully, unambiguously known. We further utilize this method to inform the instantiation of samples for crystal plasticity simulations, and demonstrate the significant improvement in deformation field predictions when utilizing this reconstruction method compared to using results from traditional PLM.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"222 ","pages":"Article 114841"},"PeriodicalIF":4.8,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474578","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}
Single Point Incremental Forming of titanium alloys for biomedical implants presents a unique challenge in balancing geometrical accuracy with the control of residual stresses. The proposed methodology introduces a novel curvature-driven adaptive toolpath for incremental forming, overcoming the limitations of conventional constant depth spiral and existing adaptive strategies. Unlike STL-based adaptive methods that rely on volumetric error correction by adding slices between consecutive layers, this approach optimizes the toolpath by removing redundant slices. By adjusting slice, the process assigns density values according to local curvature fluctuations thus creating more efficient forming while reducing forming time. Electron Backscatter Diffraction is utilized to measure the evolution of microstructure through an evaluation of misorientation distribution, deformation twinning and geometrically necessary dislocation density. X-ray diffraction technology and micro-scale residual stress measurement techniques are used to measure macro and micro residual stress fields in the produced implants. The present work correlates the tool path strategies with the observed residual stress distribution along with microstructural characteristics which uncovered the underlying deformation mechanism in implants formed by SPIF. Results highlight that adaptive tool path-driven SPIF process led to decreased amounts of residual stress while creating more uniform stress patterns within Ti-Grade 2 implants. The implant formed with adaptive tool path resulted in higher homogeneity in stress distribution with lower localized strain concentrations in comparison to those formed with conventional tool paths. In addition, microstructural characteristics denoted more uniform plastic deformation across the formed implant. The study demonstrates that the modifications in SPIF tool path bring superior results in product quality. Achieving desired residual stress states and microstructural characteristics becomes possible through SPIF which delivers improved dimensional accuracy and reliability of the formed Ti-Grade 2 implants.
{"title":"Multiscale residual stress analysis and microstructure characterization of Ti-grade 2 implant fabricated by adaptive tool path-driven SPIF process","authors":"Arun Sharma , Parnika Shrivastava , Aniket Nagargoje , Amrut Mulay","doi":"10.1016/j.matchar.2025.114861","DOIUrl":"10.1016/j.matchar.2025.114861","url":null,"abstract":"<div><div>Single Point Incremental Forming of titanium alloys for biomedical implants presents a unique challenge in balancing geometrical accuracy with the control of residual stresses. The proposed methodology introduces a novel curvature-driven adaptive toolpath for incremental forming, overcoming the limitations of conventional constant depth spiral and existing adaptive strategies. Unlike STL-based adaptive methods that rely on volumetric error correction by adding slices between consecutive layers, this approach optimizes the toolpath by removing redundant slices. By adjusting slice, the process assigns density values according to local curvature fluctuations thus creating more efficient forming while reducing forming time. Electron Backscatter Diffraction is utilized to measure the evolution of microstructure through an evaluation of misorientation distribution, deformation twinning and geometrically necessary dislocation density. X-ray diffraction technology and micro-scale residual stress measurement techniques are used to measure macro and micro residual stress fields in the produced implants. The present work correlates the tool path strategies with the observed residual stress distribution along with microstructural characteristics which uncovered the underlying deformation mechanism in implants formed by SPIF. Results highlight that adaptive tool path-driven SPIF process led to decreased amounts of residual stress while creating more uniform stress patterns within Ti-Grade 2 implants. The implant formed with adaptive tool path resulted in higher homogeneity in stress distribution with lower localized strain concentrations in comparison to those formed with conventional tool paths. In addition, microstructural characteristics denoted more uniform plastic deformation across the formed implant. The study demonstrates that the modifications in SPIF tool path bring superior results in product quality. Achieving desired residual stress states and microstructural characteristics becomes possible through SPIF which delivers improved dimensional accuracy and reliability of the formed Ti-Grade 2 implants.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"222 ","pages":"Article 114861"},"PeriodicalIF":4.8,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487248","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 : 2025-02-18DOI: 10.1016/j.matchar.2025.114847
Jianping Ouyang , Liejun Li , Xianqiang Xing , Zhuoran Li , Siming Huang , Lang Liu , Zhichao Luo , Zhengwu Peng
Flash tempering has emerged as a sustainable and energy-efficient method for optimizing the mechanical properties of martensitic steels. This work investigates the temperature-dependent substructural evolution and mechanical properties of a high‑carbon low-alloy martensitic steel subjected to flash tempering. Results show that dislocation density decreases sharply with increasing tempering temperature, stabilizing at a high level (∼1015 m−2). Meanwhile, carbides evolve from dense intragranular η-carbides at lower temperatures (439 °C) to a mixture of η and θ-carbides, and finally to predominantly θ-carbides at higher temperatures (524 °C). Optimal mechanical properties are achieved at 473 °C, with an ultimate tensile strength of 2077 MPa, total elongation of 15.1 %, and fracture toughness of 49.3 MPa·m1/2. This balance is attributed to the synergistic effects of partially recovered dislocations, finely dispersed η-carbides, and intergranular θ-carbides, which collectively enhance ductility and toughness while sustaining ultra-high strength. These findings underscore the critical role of dislocation-precipitate interactions in tuning the microstructure and mechanical properties of flash-tempered martensitic steels.
{"title":"Strength-ductility-toughness balance in flash-tempered martensitic steel: Role of dislocation-precipitate interactions","authors":"Jianping Ouyang , Liejun Li , Xianqiang Xing , Zhuoran Li , Siming Huang , Lang Liu , Zhichao Luo , Zhengwu Peng","doi":"10.1016/j.matchar.2025.114847","DOIUrl":"10.1016/j.matchar.2025.114847","url":null,"abstract":"<div><div>Flash tempering has emerged as a sustainable and energy-efficient method for optimizing the mechanical properties of martensitic steels. This work investigates the temperature-dependent substructural evolution and mechanical properties of a high‑carbon low-alloy martensitic steel subjected to flash tempering. Results show that dislocation density decreases sharply with increasing tempering temperature, stabilizing at a high level (∼10<sup>15</sup> m<sup>−2</sup>). Meanwhile, carbides evolve from dense intragranular η-carbides at lower temperatures (439 °C) to a mixture of η and θ-carbides, and finally to predominantly θ-carbides at higher temperatures (524 °C). Optimal mechanical properties are achieved at 473 °C, with an ultimate tensile strength of 2077 MPa, total elongation of 15.1 %, and fracture toughness of 49.3 MPa·m<sup>1/2</sup>. This balance is attributed to the synergistic effects of partially recovered dislocations, finely dispersed η-carbides, and intergranular θ-carbides, which collectively enhance ductility and toughness while sustaining ultra-high strength. These findings underscore the critical role of dislocation-precipitate interactions in tuning the microstructure and mechanical properties of flash-tempered martensitic steels.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"222 ","pages":"Article 114847"},"PeriodicalIF":4.8,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479870","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 : 2025-02-18DOI: 10.1016/j.matchar.2025.114858
Jinghui Fan , Minming Zou , Sifan Tan , Guangyu Zhu , Langfeng Zhu , Baowen Fu , Chao Qiang , Zhixiang Wu , Wenjing Chen , Xiaowu Hu , Tao Xu , Xiongxin Jiang
This paper investigates the effects of Cu@Sn@Ag (CSA) core shell particles and ultrasonic treatment on the microstructures and mechanical properties of Sn-3.0Ag-0.5Cu (SAC305) solder joints. The results indicated the optimum content of CSA particles was 0.05 wt%, and the optimum ultrasonic treatment time for the composite solder with CSA particles was 5 s. The study found that the ultrasonic treatment resulted in the dispersion of the agglomerated CSA particles, a reduction in the number of pores in the solder and a significant improvement in the shear strength of the solder joints. But too much ultrasound time increased IMC thickness and decreased the shear strength of solder joints. Both CSA particles and ultrasonication caused the solder joint to change from a brittle-tough hybrid fracture mode to a ductile fracture mode. A 30.58 % increase in shear strength was observed in solder joints with CSA particles added and ultrasound treated, compared to the original joints. Furthermore, the EBSD results showed that solder containing CSA particles had more nucleation sites, resulting in a finer grain size of the composite solder. The ageing experiment showed that after 360 h of ageing, the grain size of the solder joints containing CSA particles was 15.34 % smaller than the original joints.
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