Pub Date : 2026-01-09DOI: 10.1016/j.matchar.2026.116004
Zhuang Liu , Yue yan Qi , Jun Hui
This study employs first-principles and thermodynamic calculations to elucidate how elemental segregation governs grain boundary (GB) stability in AlMg nanoalloys. i) A positive linear correlation is established between segregation energy and interfacial stability, highlighting the dominant role of free surface (FS) energy in determining GB strength. ii) Compressive stress enhances both segregation and GB stability, whereas FS characteristics remain largely unaffected. At elevated temperatures, crack stability is controlled by the combined effects of formation energy and bond contraction between undercoordinated atoms. iii) The synergistic effect of nanograin size and elemental segregation significantly improves both hardness and high-temperature stability. These findings provide fundamental insight into stress–segregation coupling and offer guidance for designing thermally stable, high-strength nanoalloys.
{"title":"Fracture behavior and strengthening mechanisms of grain boundaries in AlMg alloys","authors":"Zhuang Liu , Yue yan Qi , Jun Hui","doi":"10.1016/j.matchar.2026.116004","DOIUrl":"10.1016/j.matchar.2026.116004","url":null,"abstract":"<div><div>This study employs first-principles and thermodynamic calculations to elucidate how elemental segregation governs grain boundary (GB) stability in Al<img>Mg nanoalloys. i) A positive linear correlation is established between segregation energy and interfacial stability, highlighting the dominant role of free surface (FS) energy in determining GB strength. ii) Compressive stress enhances both segregation and GB stability, whereas FS characteristics remain largely unaffected. At elevated temperatures, crack stability is controlled by the combined effects of formation energy and bond contraction between undercoordinated atoms. iii) The synergistic effect of nanograin size and elemental segregation significantly improves both hardness and high-temperature stability. These findings provide fundamental insight into stress–segregation coupling and offer guidance for designing thermally stable, high-strength nanoalloys.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"232 ","pages":"Article 116004"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978821","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 : 2026-01-09DOI: 10.1016/j.matchar.2026.116000
Qicong Liu , Lei Jia , Gen Li , Huasong Liu , Kun Chen , Limin Wang , Xikou He
Ni-Cr-Al-Ti alloy, a precipitation-strengthened nickel-based superalloy, is widely employed in high-temperature structural components. However, its ingot is susceptible to thermal cracking caused by residual stresses and elemental segregation during solidification, which significantly impairs yield. This study systematically investigates the effects of various stress-relief annealing processes on the microstructure evolution and mechanical properties of Ni-Cr-Al-Ti alloy ingots. Using thermodynamic calculations, differential scanning calorimetry (DSC), high-temperature optical scanning (HTOS) in-situ observations, electron probe microanalysis (EPMA), electron backscatter diffraction (EBSD), and mechanical testing, the relationships between crack formation, elemental segregation, precipitate phase type, and residual stress were thoroughly examined. The results reveal that elements such as Ti and Nb exhibit pronounced positive segregation between dendrites, which facilitates the precipitation of MC carbides and acicular δ phases, serving as nucleation sites for microcracks. Annealing at 1050 °C effectively dissolves the δ phase, reduces and disperses the size of the MC phase, and increases the volume fraction of γ' phase to 35.25%. Consequently, the tensile strength of the alloy at room temperature improves to 715.5 MPa, and residual stress is substantially reduced, thereby inhibiting crack propagation. Although annealing at 1150 °C further enhances microstructural homogeneity, the re-dissolution of the γ' phase diminishes its strengthening effect. This study identifies 1050 °C as the optimal annealing process, providing a theoretical foundation and process guidance for the production of high-alloy Ni-Cr-Al-Ti alloy ingots with a low crack rate.
{"title":"Microstructure and properties evolution of Ni-Cr-Al-Ti alloy during stress relief annealing process","authors":"Qicong Liu , Lei Jia , Gen Li , Huasong Liu , Kun Chen , Limin Wang , Xikou He","doi":"10.1016/j.matchar.2026.116000","DOIUrl":"10.1016/j.matchar.2026.116000","url":null,"abstract":"<div><div>Ni-Cr-Al-Ti alloy, a precipitation-strengthened nickel-based superalloy, is widely employed in high-temperature structural components. However, its ingot is susceptible to thermal cracking caused by residual stresses and elemental segregation during solidification, which significantly impairs yield. This study systematically investigates the effects of various stress-relief annealing processes on the microstructure evolution and mechanical properties of Ni-Cr-Al-Ti alloy ingots. Using thermodynamic calculations, differential scanning calorimetry (DSC), high-temperature optical scanning (HTOS) in-situ observations, electron probe microanalysis (EPMA), electron backscatter diffraction (EBSD), and mechanical testing, the relationships between crack formation, elemental segregation, precipitate phase type, and residual stress were thoroughly examined. The results reveal that elements such as Ti and Nb exhibit pronounced positive segregation between dendrites, which facilitates the precipitation of MC carbides and acicular δ phases, serving as nucleation sites for microcracks. Annealing at 1050 °C effectively dissolves the δ phase, reduces and disperses the size of the MC phase, and increases the volume fraction of γ' phase to 35.25%. Consequently, the tensile strength of the alloy at room temperature improves to 715.5 MPa, and residual stress is substantially reduced, thereby inhibiting crack propagation. Although annealing at 1150 °C further enhances microstructural homogeneity, the re-dissolution of the γ' phase diminishes its strengthening effect. This study identifies 1050 °C as the optimal annealing process, providing a theoretical foundation and process guidance for the production of high-alloy Ni-Cr-Al-Ti alloy ingots with a low crack rate.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"232 ","pages":"Article 116000"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978818","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 : 2026-01-09DOI: 10.1016/j.matchar.2026.116008
Minglei Dong, Lan Chen, Xuan Tao, Dingwei Zhu, Xinzhou Zhang, Xudong Ren
In this study, dissimilar high-strength 7075/2024 aluminum alloy samples with an interlaced layered structure were fabricated using Additive Friction Stir Deposition (AFSD). Three different heat treatment schemes (HT-1, HT-2, and HT-3) were designed and applied to the deposited samples. For the first time, a systematic analysis was conducted on the effects of different heat treatments on the microstructure, grain evolution, precipitation behavior, and mechanical properties of the deposited layers. The results revealed that heat treatment induced significant abnormal grain growth in both the 7075 and 2024 layers, with average grain sizes increasing from approximately 1.3 μm in the as-deposited samples to around 120 μm. Moreover, heat treatment significantly improved the precipitation behavior and microstructural compatibility of the AFSD samples, thereby enhancing their microhardness and tensile properties. Notably, under the HT-1 condition (460 °C-2 h + 120 °C-12 h), fine and dispersed η' and S′ phases were precipitated in the 7075 and 2024 layers, respectively, resulting in a remarkable improvement in comprehensive mechanical performance. The HT-1 sample exhibited a 62.8% increase in tensile strength and a 15.4% increase in elongation along the build direction compared to the as-deposited sample. In addition, the microhardness of the 7075 layer in the HT-2 condition (460 °C-2 h + 120 °C-24 h) was nearly restored to the level of the original wrought material. This study elucidates the mechanisms by which heat treatment regulates the microstructure and properties of layered dissimilar aluminum alloys, providing theoretical guidance for the structural optimization of multilayer dissimilar aluminum alloy components.
采用添加剂搅拌摩擦沉积法（AFSD）制备了具有交错层状结构的不同高强7075/2024铝合金样品。设计了三种不同的热处理方案（HT-1、HT-2和HT-3），并对沉积样品进行了处理。首次系统分析了不同热处理方式对堆积层显微组织、晶粒演化、析出行为和力学性能的影响。结果表明，热处理导致7075和2024层的晶粒明显异常长大，平均晶粒尺寸从沉积样的1.3 μm左右增加到120 μm左右。此外，热处理显著改善了AFSD样品的析出行为和显微组织相容性，从而提高了AFSD样品的显微硬度和拉伸性能。值得注意的是，在HT-1条件下（460℃-2 h + 120℃-12 h）， 7075层和2024层分别析出细小分散的η′和S′相，综合力学性能得到显著提高。与沉积态相比，HT-1试样的抗拉强度提高了62.8%，延伸率提高了15.4%。另外，7075层在HT-2条件下（460℃-2 h + 120℃-24 h）的显微硬度几乎恢复到原变形材料的水平。本研究阐明了热处理对层状异种铝合金组织和性能的调控机理，为多层异种铝合金构件的结构优化提供理论指导。
{"title":"Effect of heat treatment on the microstructure and mechanical properties of dissimilar high-strength 7075–2024 Aluminum alloys fabricated by additive friction stir deposition","authors":"Minglei Dong, Lan Chen, Xuan Tao, Dingwei Zhu, Xinzhou Zhang, Xudong Ren","doi":"10.1016/j.matchar.2026.116008","DOIUrl":"10.1016/j.matchar.2026.116008","url":null,"abstract":"<div><div>In this study, dissimilar high-strength 7075/2024 aluminum alloy samples with an interlaced layered structure were fabricated using Additive Friction Stir Deposition (AFSD). Three different heat treatment schemes (HT-1, HT-2, and HT-3) were designed and applied to the deposited samples. For the first time, a systematic analysis was conducted on the effects of different heat treatments on the microstructure, grain evolution, precipitation behavior, and mechanical properties of the deposited layers. The results revealed that heat treatment induced significant abnormal grain growth in both the 7075 and 2024 layers, with average grain sizes increasing from approximately 1.3 μm in the as-deposited samples to around 120 μm. Moreover, heat treatment significantly improved the precipitation behavior and microstructural compatibility of the AFSD samples, thereby enhancing their microhardness and tensile properties. Notably, under the HT-1 condition (460 °C-2 h + 120 °C-12 h), fine and dispersed η' and S′ phases were precipitated in the 7075 and 2024 layers, respectively, resulting in a remarkable improvement in comprehensive mechanical performance. The HT-1 sample exhibited a 62.8% increase in tensile strength and a 15.4% increase in elongation along the build direction compared to the as-deposited sample. In addition, the microhardness of the 7075 layer in the HT-2 condition (460 °C-2 h + 120 °C-24 h) was nearly restored to the level of the original wrought material. This study elucidates the mechanisms by which heat treatment regulates the microstructure and properties of layered dissimilar aluminum alloys, providing theoretical guidance for the structural optimization of multilayer dissimilar aluminum alloy components.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"232 ","pages":"Article 116008"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978815","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 : 2026-01-09DOI: 10.1016/j.matchar.2026.116006
Yun-Hsuan Wu , Isshu Lee , Laxman Bhatta , Roberto B. Figueiredo , Megumi Kawasaki , Melissa K. Santala
Al-1043 sheets were processed at room temperature using a continuous processing technique that combines circumferential and channel-angle shear deformation called cold angular rolling process (CARP), a technique which is intended to induce severe plastic deformation (SPD). The microstructure and mechanical properties were characterized before CARP and after one, two, and four passes of CARP. Scanning electron microscopy electron backscattered diffraction results showed each pass of CARP increased the density of geometrically necessary dislocations (GND) and low-angle grain boundaries (LAGBs). Grain refinement did not appear to be induced even after four CARP passes. Vickers microhardness and miniature tensile testing with digital image correlation (DIC) analysis showed corresponding increases in hardness and strength, which can be related to the changes in dislocation density through the Taylor relationship. During tensile testing, DIC revealed evidence of increased strain in the vicinity of indents caused by the roller knurls. The comparison of the effects of knurl marks on the microstructure revealed that the density of LAGBs and GND, as well as the grain size, and grain shapes (aspect ratio) were similar below and between knurl marks for both one and four passes of CARP, suggesting the local increase in strain is primarily a geometric effect. This study provides detailed microstructure characterization and connects it to the mechanical properties of aluminum sheets deformed by this new processing technique.
{"title":"Microstructural characterization and mechanical properties of Al-1043 produced by cold angular roll processing","authors":"Yun-Hsuan Wu , Isshu Lee , Laxman Bhatta , Roberto B. Figueiredo , Megumi Kawasaki , Melissa K. Santala","doi":"10.1016/j.matchar.2026.116006","DOIUrl":"10.1016/j.matchar.2026.116006","url":null,"abstract":"<div><div>Al-1043 sheets were processed at room temperature using a continuous processing technique that combines circumferential and channel-angle shear deformation called cold angular rolling process (CARP), a technique which is intended to induce severe plastic deformation (SPD). The microstructure and mechanical properties were characterized before CARP and after one, two, and four passes of CARP. Scanning electron microscopy electron backscattered diffraction results showed each pass of CARP increased the density of geometrically necessary dislocations (GND) and low-angle grain boundaries (LAGBs). Grain refinement did not appear to be induced even after four CARP passes. Vickers microhardness and miniature tensile testing with digital image correlation (DIC) analysis showed corresponding increases in hardness and strength, which can be related to the changes in dislocation density through the Taylor relationship. During tensile testing, DIC revealed evidence of increased strain in the vicinity of indents caused by the roller knurls. The comparison of the effects of knurl marks on the microstructure revealed that the density of LAGBs and GND, as well as the grain size, and grain shapes (aspect ratio) were similar below and between knurl marks for both one and four passes of CARP, suggesting the local increase in strain is primarily a geometric effect. This study provides detailed microstructure characterization and connects it to the mechanical properties of aluminum sheets deformed by this new processing technique.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"232 ","pages":"Article 116006"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978817","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 : 2026-01-08DOI: 10.1016/j.matchar.2026.115975
Yongdong Yu , Qian Yang , Degang Zhao , Futian Liu , Yongting Zheng , Xiaodong He , Wanjun Yu
Strengthening and toughening of nano-precipitates are a critical approach for preparing high-performance nanocomposite ceramics. However, the precipitation mode and mechanism of uniformly Al2O3-ZrO2 supersaturated solid solutions (AZ-SS) remain underexplored. Here, the effect of heat-treatment temperature, duration and Al2O3 content (36 mol% and 57 mol%) on the nanoprecipitation of AZ-SS was systematically investigated. Results revealed that the initial nanoprecipitation temperature decreased with increasing Al2O3 content. Experiments and phase-field simulations revealed dual precipitation pathways: Al2O3 from ZrO2(SS) and ZrO2 from Al2O3(SS), forming different Al2O3-ZrO2 nanocomposite structures with different Al2O3 content. With low alumina content (36 mol%, ATZ), AZ-SS tends to form a worm-like structure, while with high alumina content (57 mol%, ZTA), AZ-SS tends to form a spherical particle structure after heat-treatment. Furthermore, the higher the heat-treatment temperature or the longer the holding time, the easier it is to reach the nanoprecipitation limit of AZ-SS. These findings highlight the critical role of compositional tuning and thermal processing in achieving tailored nanostructures, providing a scalable pathway for high-performance ceramic materials.
{"title":"Synergistic phase-microstructure regulation of Al2O3-ZrO2 solid solutions via compositional and heat-treatment pathways","authors":"Yongdong Yu , Qian Yang , Degang Zhao , Futian Liu , Yongting Zheng , Xiaodong He , Wanjun Yu","doi":"10.1016/j.matchar.2026.115975","DOIUrl":"10.1016/j.matchar.2026.115975","url":null,"abstract":"<div><div>Strengthening and toughening of nano-precipitates are a critical approach for preparing high-performance nanocomposite ceramics. However, the precipitation mode and mechanism of uniformly Al<sub>2</sub>O<sub>3</sub>-ZrO<sub>2</sub> supersaturated solid solutions (AZ-SS) remain underexplored. Here, the effect of heat-treatment temperature, duration and Al<sub>2</sub>O<sub>3</sub> content (36 mol% and 57 mol%) on the nanoprecipitation of AZ-SS was systematically investigated. Results revealed that the initial nanoprecipitation temperature decreased with increasing Al<sub>2</sub>O<sub>3</sub> content. Experiments and phase-field simulations revealed dual precipitation pathways: Al<sub>2</sub>O<sub>3</sub> from ZrO<sub>2</sub>(SS) and ZrO<sub>2</sub> from Al<sub>2</sub>O<sub>3</sub>(SS), forming different Al<sub>2</sub>O<sub>3</sub>-ZrO<sub>2</sub> nanocomposite structures with different Al<sub>2</sub>O<sub>3</sub> content. With low alumina content (36 mol%, ATZ), AZ-SS tends to form a worm-like structure, while with high alumina content (57 mol%, ZTA), AZ-SS tends to form a spherical particle structure after heat-treatment. Furthermore, the higher the heat-treatment temperature or the longer the holding time, the easier it is to reach the nanoprecipitation limit of AZ-SS. These findings highlight the critical role of compositional tuning and thermal processing in achieving tailored nanostructures, providing a scalable pathway for high-performance ceramic materials.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"232 ","pages":"Article 115975"},"PeriodicalIF":5.5,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978843","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 : 2026-01-08DOI: 10.1016/j.matchar.2026.116001
Caidong Zhang , Guangwei Huang , Zhiyan Sun , Jiarui Guo , Xue Su , Zhixin Gao , Yihao Zheng , Jie Li , Shuai Ren , Xiliang Zhang , Yindong Shi
Martensitic steels are renowned for their ultrahigh strength but often suffer from low ductility due to limited work hardening capacities. Here, we developed a novel heterostructured martensitic steel, consisting of retained austenite, twinned martensite and lath martensite along with metastable shearable carbides. This specific heterostructure achieved a simultaneous enhancement in work hardening capacity, uniform ductility (εu ∼ 7.1 ± 0.9%), yield strength (σy ∼ 1.54 ± 0.01 GPa) and ultimate tensile strength (σUTS ∼ 2.1 ± 0.017 GPa). The increase in strength was primarily attributed to the precipitation of high-density carbides and hetero-deformation induced (HDI) strengthening. The sequential activation of the transformation-induced plasticity (TRIP) effect, HDI work hardening and the shearing of carbides by dislocations contributed to the improved strain hardening and uniform ductility. This study presents an approach to enhancing both the work-hardening capabilities, ductility and strength of martensitic steels through the design of a novel heterostructure.
{"title":"Simultaneously enhancing work hardening and strength in a novel heterostructured steel","authors":"Caidong Zhang , Guangwei Huang , Zhiyan Sun , Jiarui Guo , Xue Su , Zhixin Gao , Yihao Zheng , Jie Li , Shuai Ren , Xiliang Zhang , Yindong Shi","doi":"10.1016/j.matchar.2026.116001","DOIUrl":"10.1016/j.matchar.2026.116001","url":null,"abstract":"<div><div>Martensitic steels are renowned for their ultrahigh strength but often suffer from low ductility due to limited work hardening capacities. Here, we developed a novel heterostructured martensitic steel, consisting of retained austenite, twinned martensite and lath martensite along with metastable shearable carbides. This specific heterostructure achieved a simultaneous enhancement in work hardening capacity, uniform ductility (<em>ε</em><sub><em>u</em></sub> ∼ 7.1 ± 0.9%), yield strength (<em>σ</em><sub><em>y</em></sub> ∼ 1.54 ± 0.01 GPa) and ultimate tensile strength (<em>σ</em><sub><em>UTS</em></sub> ∼ 2.1 ± 0.017 GPa). The increase in strength was primarily attributed to the precipitation of high-density carbides and hetero-deformation induced (HDI) strengthening. The sequential activation of the transformation-induced plasticity (TRIP) effect, HDI work hardening and the shearing of carbides by dislocations contributed to the improved strain hardening and uniform ductility. This study presents an approach to enhancing both the work-hardening capabilities, ductility and strength of martensitic steels through the design of a novel heterostructure.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"232 ","pages":"Article 116001"},"PeriodicalIF":5.5,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927971","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 : 2026-01-08DOI: 10.1016/j.matchar.2026.115999
Congcong Bian , Liangxin Wen , Xuedong Wu , Cheng Cheng , Zhaojie Wan , Penghui Li , Yangyang Liu , Xiaobin Shi
Effect of cold-drawn deformation and annealing temperature on reverse transformation of pre-deformed nanocrystalline Ni50Ti50 alloys was investigated. The Ni50Ti50 alloy wires were cold-drawn into samples with 20%–70% deformations and annealed at 350–500 °C, then the properties of the samples were studied by means of differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) analysis. The results confirmed that the 350 °C-annealed samples subjected to 60% and 70% cold-drawn deformation exhibit pseudoelasticity when strained to 8%. In contrast, all other samples retained large unrecovered strains, indicating a non-pseudoelastic response. The unrecovered strains and reverse transformation temperatures of the annealed 20% cold-drawn samples are insensitive to annealing temperature, because 20% cold work is insufficient to trigger recrystallization, leading to minimal microstructural changes. In contrast, specimens with higher cold drawing percentages (40–70%) demonstrate pronounced annealing temperature dependence, where the reverse transformation temperatures increase significantly with elevated annealing temperatures due to the recrystallization and subsequent grain growth. The reverse transformation temperatures of the 12%-tension samples are significantly higher than that of the as-annealed counterparts, indicating that martensite reorientation in grains occurred during the 12% tension cycle, which stabilizes the B19’ martensite.
{"title":"Effect of cold-drawn deformation and annealing temperature on reverse transformation of pre-deformed nanocrystalline Ni50Ti50 alloys","authors":"Congcong Bian , Liangxin Wen , Xuedong Wu , Cheng Cheng , Zhaojie Wan , Penghui Li , Yangyang Liu , Xiaobin Shi","doi":"10.1016/j.matchar.2026.115999","DOIUrl":"10.1016/j.matchar.2026.115999","url":null,"abstract":"<div><div>Effect of cold-drawn deformation and annealing temperature on reverse transformation of pre-deformed nanocrystalline Ni<sub>50</sub>Ti<sub>50</sub> alloys was investigated. The Ni<sub>50</sub>Ti<sub>50</sub> alloy wires were cold-drawn into samples with 20%–70% deformations and annealed at 350–500 °C, then the properties of the samples were studied by means of differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) analysis. The results confirmed that the 350 °C-annealed samples subjected to 60% and 70% cold-drawn deformation exhibit pseudoelasticity when strained to 8%. In contrast, all other samples retained large unrecovered strains, indicating a non-pseudoelastic response. The unrecovered strains and reverse transformation temperatures of the annealed 20% cold-drawn samples are insensitive to annealing temperature, because 20% cold work is insufficient to trigger recrystallization, leading to minimal microstructural changes. In contrast, specimens with higher cold drawing percentages (40–70%) demonstrate pronounced annealing temperature dependence, where the reverse transformation temperatures increase significantly with elevated annealing temperatures due to the recrystallization and subsequent grain growth. The reverse transformation temperatures of the 12%-tension samples are significantly higher than that of the as-annealed counterparts, indicating that martensite reorientation in grains occurred during the 12% tension cycle, which stabilizes the B19’ martensite.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"232 ","pages":"Article 115999"},"PeriodicalIF":5.5,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927968","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 : 2026-01-08DOI: 10.1016/j.matchar.2026.115997
Xuqin Li , Qining Zheng , Jing He , Xuehan Ma , Yi Zhang , Chengyu Zhang , Yongsheng Liu
The demand for silicon carbide fiber-reinforced silicon carbide (SiCf/SiC) composites with enhanced creep resistance has become increasingly critical for long-term applications exceeding 1650 °C in air. Their creep lifetime is predominantly governed by their proportional limit stress (PLS) and the intrinsic creep resistance of the SiC fibers. Herein, we report the fabrication of SiCf/SiC composites with Cansas™ 3303 SiC fibers featuring a PyC and in-situ grown BN (PyC-iBN) bilayer interphase. A two-dimensional eight-harness satin preform was utilized. The PyC-iBN interphase (∼0.6 μm) was synthesized in situ by chlorination and carbothermal reduction methods. The resulting composite prepared by chemical vapor infiltration (CVI) exhibited an outstanding PLS of 248.66 MPa, which endowed it with superior creep resistance, demonstrated by a 100-h creep life at 1650 °C under 35 MPa in air. Fractographic analysis revealed extensive fiber pull-out, interfacial debonding, and sliding, indicating that the PyC-iBN bilayer interphase effectively facilitated load transfer and imparted remarkable toughening. This work provided a viable strategy for designing high-performance SiCf/SiC composites for ultra-high-temperature applications.
{"title":"Achieving high creep resistance in SiCf/SiC composites at 1650 °C in air by engineering a PyC-iBN bilayer interphase","authors":"Xuqin Li , Qining Zheng , Jing He , Xuehan Ma , Yi Zhang , Chengyu Zhang , Yongsheng Liu","doi":"10.1016/j.matchar.2026.115997","DOIUrl":"10.1016/j.matchar.2026.115997","url":null,"abstract":"<div><div>The demand for silicon carbide fiber-reinforced silicon carbide (SiC<sub>f</sub>/SiC) composites with enhanced creep resistance has become increasingly critical for long-term applications exceeding 1650 °C in air. Their creep lifetime is predominantly governed by their proportional limit stress (PLS) and the intrinsic creep resistance of the SiC fibers. Herein, we report the fabrication of SiC<sub>f</sub>/SiC composites with Cansas™ 3303 SiC fibers featuring a PyC and in-situ grown BN (PyC-iBN) bilayer interphase. A two-dimensional eight-harness satin preform was utilized. The PyC-iBN interphase (∼0.6 μm) was synthesized in situ by chlorination and carbothermal reduction methods. The resulting composite prepared by chemical vapor infiltration (CVI) exhibited an outstanding PLS of 248.66 MPa, which endowed it with superior creep resistance, demonstrated by a 100-h creep life at 1650 °C under 35 MPa in air. Fractographic analysis revealed extensive fiber pull-out, interfacial debonding, and sliding, indicating that the PyC-iBN bilayer interphase effectively facilitated load transfer and imparted remarkable toughening. This work provided a viable strategy for designing high-performance SiC<sub>f</sub>/SiC composites for ultra-high-temperature applications.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"232 ","pages":"Article 115997"},"PeriodicalIF":5.5,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978695","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 : 2026-01-08DOI: 10.1016/j.matchar.2026.115994
Qiang Wang , Zhao-Hui Zhang , Xing-Wang Cheng , Xiao-Tong Jia , Jin-Zhao Zhou , Wen-Jun Li
The research fabricated a titanium matrix composite with multi-scale reinforcements and examined its compressive behavior and microstructural evolution across different strain rates. The composite showed limited strain rate sensitivity at low rates, with yield strength increasing only marginally from 1288 MPa (0.001 s−1) to 1312 MPa (0.1 s−1). In contrast, high strain rates induced significant strain rate hardening: yield strengths reached 1641 MPa, 1728 MPa, and 1816 MPa at 1243 s−1, 2207 s−1, and 3342 s−1, representing increases of 27.4% ∼ 41.0% over the quasi-static value. Deformation mechanism analysis indicated a transition from dislocation slip (activation volume ∼ 48 b3) at low rates to nucleation-dominated mechanisms (∼1.5 b3) at high rates, explaining the observed hardening. Under dynamic shear, localized thermal softening from plastic work overcame strain hardening, triggering adiabatic shear bands. TiC/matrix interfaces failed due to thermal mismatch and shear, forming microvoids that initiated cracks. In contrast, (TiZr)5Si3/matrix interfaces retained excellent integrity, delaying damage progression.
{"title":"Dynamic compression properties and failure mechanisms of (TiC + (TiZr)5Si3)/TA15 composites","authors":"Qiang Wang , Zhao-Hui Zhang , Xing-Wang Cheng , Xiao-Tong Jia , Jin-Zhao Zhou , Wen-Jun Li","doi":"10.1016/j.matchar.2026.115994","DOIUrl":"10.1016/j.matchar.2026.115994","url":null,"abstract":"<div><div>The research fabricated a titanium matrix composite with multi-scale reinforcements and examined its compressive behavior and microstructural evolution across different strain rates. The composite showed limited strain rate sensitivity at low rates, with yield strength increasing only marginally from 1288 MPa (0.001 s<sup>−1</sup>) to 1312 MPa (0.1 s<sup>−1</sup>). In contrast, high strain rates induced significant strain rate hardening: yield strengths reached 1641 MPa, 1728 MPa, and 1816 MPa at 1243 s<sup>−1</sup>, 2207 s<sup>−1</sup>, and 3342 s<sup>−1</sup>, representing increases of 27.4% ∼ 41.0% over the quasi-static value. Deformation mechanism analysis indicated a transition from dislocation slip (activation volume ∼ 48 b<sup>3</sup>) at low rates to nucleation-dominated mechanisms (∼1.5 b<sup>3</sup>) at high rates, explaining the observed hardening. Under dynamic shear, localized thermal softening from plastic work overcame strain hardening, triggering adiabatic shear bands. TiC/matrix interfaces failed due to thermal mismatch and shear, forming microvoids that initiated cracks. In contrast, (TiZr)<sub>5</sub>Si<sub>3</sub>/matrix interfaces retained excellent integrity, delaying damage progression.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"232 ","pages":"Article 115994"},"PeriodicalIF":5.5,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978699","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 : 2026-01-08DOI: 10.1016/j.matchar.2026.115998
Hao Zhang , Le Zai , Yun Wang , Xiaohuai Xue
The fusion zone (FZ) of tungsten inert gas (TIG) welded Ti2AlNb-based alloy typically exhibits undesirable coarse columnar grains, which can lead to solidification defects and degraded mechanical properties. To address this issue, this study designed and fabricated a novel alloy wire embedded with nano-ZrO₂ particles, aiming to promote the columnar-to-equiaxed transition (CET) in the FZ of TIG-welded Ti2AlNb-based alloy. Results reveal that nano-ZrO₂ particles preferentially segregate along grain boundaries, forming continuous nanoparticle layers that encapsulate growing grains. This specific nanoparticle distribution reduces the solute concentration gradient at the tips of dendrites, thereby exerting a significant inhibitory effect on grain growth. Notably, a fully equiaxed microstructure was achieved in the FZ: the average grain size was reduced by 42%—from 212.4 μm (coarse columnar dendrites in the unmodified FZ) to 125.6 μm. Concurrently, the equiaxed grains exhibited reduced proportions of low-angle grain boundaries (LAGBs) and diminished kernel average misorientation (KAM), synergistically enhancing plastic deformation capacity. This microstructural optimization significantly improved joint ductility, yielding 225.25% higher elongation at room temperature and 58.59% greater elongation at elevated temperatures.
{"title":"Achieving columnar-to-equiaxed transition in TIG-welded Ti2AlNb intermetallic alloy via nano-ZrO₂ particles","authors":"Hao Zhang , Le Zai , Yun Wang , Xiaohuai Xue","doi":"10.1016/j.matchar.2026.115998","DOIUrl":"10.1016/j.matchar.2026.115998","url":null,"abstract":"<div><div>The fusion zone (FZ) of tungsten inert gas (TIG) welded Ti2AlNb-based alloy typically exhibits undesirable coarse columnar grains, which can lead to solidification defects and degraded mechanical properties. To address this issue, this study designed and fabricated a novel alloy wire embedded with nano-ZrO₂ particles, aiming to promote the columnar-to-equiaxed transition (CET) in the FZ of TIG-welded Ti2AlNb-based alloy. Results reveal that nano-ZrO₂ particles preferentially segregate along grain boundaries, forming continuous nanoparticle layers that encapsulate growing grains. This specific nanoparticle distribution reduces the solute concentration gradient at the tips of dendrites, thereby exerting a significant inhibitory effect on grain growth. Notably, a fully equiaxed microstructure was achieved in the FZ: the average grain size was reduced by 42%—from 212.4 μm (coarse columnar dendrites in the unmodified FZ) to 125.6 μm. Concurrently, the equiaxed grains exhibited reduced proportions of low-angle grain boundaries (LAGBs) and diminished kernel average misorientation (KAM), synergistically enhancing plastic deformation capacity. This microstructural optimization significantly improved joint ductility, yielding 225.25% higher elongation at room temperature and 58.59% greater elongation at elevated temperatures.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"232 ","pages":"Article 115998"},"PeriodicalIF":5.5,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978710","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号