Pub Date : 2026-01-31DOI: 10.1016/j.matchar.2026.116104
Kuan-Chen Kung , Hsiang-Ching Chen , Yu-chen Liu , Shih-kang Lin , Wei-Hsin Chen
Phase change materials (PCMs) have garnered considerable attention for their ability to enhance energy conversion efficiency through waste heat recovery. Our designed nitrate-based PCM outperformed commercial PCM across multiple metrics, including lower melting activation energy, higher enthalpy change, and superior thermal cycling stability at low to medium temperatures. The thermal stability and surface properties of 316 stainless steel (316 SS) were evaluated before and after immersion in the designed PCM at various temperatures for various durations. GIXRD, FTIR, ESCA, and TEM analyses revealed the formation of an amorphous Fe(3+)–O thin film on the 316 SS surface, offering effective protection against corrosion from the ternary salt mixture. These findings highlight the potential of designed nitrate-based PCM for practical thermal energy storage applications in 316 SS systems operating at low to medium temperatures.
{"title":"Microstructure and thermal stability of 316 stainless steel in nitrate-based phase change materials for thermal energy storage","authors":"Kuan-Chen Kung , Hsiang-Ching Chen , Yu-chen Liu , Shih-kang Lin , Wei-Hsin Chen","doi":"10.1016/j.matchar.2026.116104","DOIUrl":"10.1016/j.matchar.2026.116104","url":null,"abstract":"<div><div>Phase change materials (PCMs) have garnered considerable attention for their ability to enhance energy conversion efficiency through waste heat recovery. Our designed nitrate-based PCM outperformed commercial PCM across multiple metrics, including lower melting activation energy, higher enthalpy change, and superior thermal cycling stability at low to medium temperatures. The thermal stability and surface properties of 316 stainless steel (316 SS) were evaluated before and after immersion in the designed PCM at various temperatures for various durations. GIXRD, FTIR, ESCA, and TEM analyses revealed the formation of an amorphous Fe(3+)–O thin film on the 316 SS surface, offering effective protection against corrosion from the ternary salt mixture. These findings highlight the potential of designed nitrate-based PCM for practical thermal energy storage applications in 316 SS systems operating at low to medium temperatures.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116104"},"PeriodicalIF":5.5,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189879","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 : 2026-01-30DOI: 10.1016/j.matchar.2026.116100
Xiaohui Yuan , Shijiao Xu , Linjie Liu , Xiangyu Zhou , Kaimeng Liu , Yujie Han , Tadatomo Suga , Chenxi Wang
To address the multifaceted challenges of low-temperature silicon-based wafer bonding, this study systematically investigates the differences in the surface states of SiO2 activated by O2 or N2 plasma with different parameters (activation power, pressure, time). The surface -OH groups activated by O2 plasma reached 49.7% under optimal parameters, accompanied by a sub-surface layer thickness of ∼3 nm and surface energy of 1.24 J/m2. The surface energy activated by N2 plasma is lower (∼0.9 J/m2). In order to explore more efficient surface activation processes for silicon oxide to meet the more challenges of rigorous heterogeneous integration, ammonia water (NH3·H2O) assisted plasma activation was carried out. This method constructs an -OH and -NH2 co-capped active surface layer and a thicker (∼5 nm) low-density sub-surface layer on the sample, the polymerization reaction products of multiple functional groups efficiently diffuse outward through the low-density layer, promoting the interfacial reactions. The synergistic effect resulted in an increase in surface energy to 2.27 J/m2. This research provides parameterization and mechanism for wafer-level low-temperature bonding. It also presents a series of efficient process solutions, providing a solid foundation for the continuous development of silicon-base devices and integrated manufacturing technologies.
{"title":"Ammonia vapor-assisted plasma activation and mechanism study for high-strength direct wafer bonding of silicon oxide","authors":"Xiaohui Yuan , Shijiao Xu , Linjie Liu , Xiangyu Zhou , Kaimeng Liu , Yujie Han , Tadatomo Suga , Chenxi Wang","doi":"10.1016/j.matchar.2026.116100","DOIUrl":"10.1016/j.matchar.2026.116100","url":null,"abstract":"<div><div>To address the multifaceted challenges of low-temperature silicon-based wafer bonding, this study systematically investigates the differences in the surface states of SiO<sub>2</sub> activated by O<sub>2</sub> or N<sub>2</sub> plasma with different parameters (activation power, pressure, time). The surface -OH groups activated by O<sub>2</sub> plasma reached 49.7% under optimal parameters, accompanied by a sub-surface layer thickness of ∼3 nm and surface energy of 1.24 J/m<sup>2</sup>. The surface energy activated by N<sub>2</sub> plasma is lower (∼0.9 J/m<sup>2</sup>). In order to explore more efficient surface activation processes for silicon oxide to meet the more challenges of rigorous heterogeneous integration, ammonia water (NH<sub>3</sub>·H<sub>2</sub>O) assisted plasma activation was carried out. This method constructs an -OH and -NH<sub>2</sub> co-capped active surface layer and a thicker (∼5 nm) low-density sub-surface layer on the sample, the polymerization reaction products of multiple functional groups efficiently diffuse outward through the low-density layer, promoting the interfacial reactions. The synergistic effect resulted in an increase in surface energy to 2.27 J/m<sup>2</sup>. This research provides parameterization and mechanism for wafer-level low-temperature bonding. It also presents a series of efficient process solutions, providing a solid foundation for the continuous development of silicon-base devices and integrated manufacturing technologies.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116100"},"PeriodicalIF":5.5,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189870","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 : 2026-01-29DOI: 10.1016/j.matchar.2026.116094
Hojoon Moon , Jung-Wook Cho
To clarify the mechanisms that govern electrical resistivity ρ in high-Fe Cu alloys, the changes in microstructure and ρ of Cu–40 wt% Fe (CFA) and Cu–40 wt% Fe-1 wt% Zr (ZCFA) alloys were examined after controlled thermomechanical processing and isothermal annealing. Zr addition induced four changes that influenced ρ: grain refinement that increased the number of grain boundaries; increased dislocation density; reduced Fe solubility that accelerated Fe precipitation; and increased volume fraction of second-phase particles. For specimens annealed at 500 °C for 4 h, grain boundaries and dislocations contributed negligibly to ρ, whereas solute atoms and precipitates had dominant effects. The solute Fe concentration in the Cu matrix remained relatively high, and us of resistivity coefficients from the literature could not reproduce the experimental data. Use of a refined assumption yielded a new solute-resistivity coefficient of 1.75 μΩ·cm/wt%, which gave excellent agreement between calculated and measured values. When normalized by material cost, ZCFA had superior strength–conductivity and cost balances compared with CFA; this result emphasizes that Zr addition can enhance both functional properties and economic competitiveness of CuFe alloys for advanced conductive structural applications.
{"title":"Effect of Zr addition on electrical resistivity mechanisms and microstructural evolution in Cu40Fe alloys","authors":"Hojoon Moon , Jung-Wook Cho","doi":"10.1016/j.matchar.2026.116094","DOIUrl":"10.1016/j.matchar.2026.116094","url":null,"abstract":"<div><div>To clarify the mechanisms that govern electrical resistivity <em>ρ</em> in high-Fe Cu alloys, the changes in microstructure and <em>ρ</em> of Cu–40 wt% Fe (CFA) and Cu–40 wt% Fe-1 wt% Zr (ZCFA) alloys were examined after controlled thermomechanical processing and isothermal annealing. Zr addition induced four changes that influenced <em>ρ</em>: grain refinement that increased the number of grain boundaries; increased dislocation density; reduced Fe solubility that accelerated Fe precipitation; and increased volume fraction of second-phase particles. For specimens annealed at 500 °C for 4 h, grain boundaries and dislocations contributed negligibly to <em>ρ</em>, whereas solute atoms and precipitates had dominant effects. The solute Fe concentration in the Cu matrix remained relatively high, and us of resistivity coefficients from the literature could not reproduce the experimental data. Use of a refined assumption yielded a new solute-resistivity coefficient of 1.75 μΩ·cm/wt%, which gave excellent agreement between calculated and measured values. When normalized by material cost, ZCFA had superior strength–conductivity and cost balances compared with CFA; this result emphasizes that Zr addition can enhance both functional properties and economic competitiveness of Cu<img>Fe alloys for advanced conductive structural applications.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116094"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189876","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 : 2026-01-29DOI: 10.1016/j.matchar.2026.116090
Shiwei Ding , Quanshun Fan , Xinyi Zhu , Tao Jiang , Guoqing Dai , Zhonggang Sun , Yanhua Guo , Wenya Li , Hai Gu , Jie Zhang
Additive friction stir deposition (AFSD) is a solid-state additive manufacturing technique with potential for fabricating large-scale aluminum alloy structures while avoiding melting–solidification. In this study, a multifactorial design was used to identify an optimal parameter set for AA6061, and a ten-layer block was fabricated for microstructure/precipitate characterization and mechanical evaluation. Results indicate that the optimal parameters are 500 rpm and 120 mm/min. The deposit exhibits a fully refined equiaxed-grain structure with an average grain size of 5–8 μm, together with pronounced dislocation multiplication. Fine Al(MnCrFe)Si particles are dispersed in grain interiors, while coarsened β (Mg₂Si) precipitates are present along grain boundaries and within grains. The multilayer block shows a hardness range of 42.5–69.6 HV0.1 and near-isotropic tensile properties among BD/LD/TD, with UTS = 219.6 ± 5.0 MPa and elongation = 21.85 ± 2.71% along BD. These results provide a processing-window reference for dimensionally reliable AFSD build-up and repair of AA6061 components requiring low defect sensitivity and near-isotropic performance.
{"title":"Microstructural evolution and mechanical properties of deposit AA6061 aluminum alloy processed by additive friction stir deposition","authors":"Shiwei Ding , Quanshun Fan , Xinyi Zhu , Tao Jiang , Guoqing Dai , Zhonggang Sun , Yanhua Guo , Wenya Li , Hai Gu , Jie Zhang","doi":"10.1016/j.matchar.2026.116090","DOIUrl":"10.1016/j.matchar.2026.116090","url":null,"abstract":"<div><div>Additive friction stir deposition (AFSD) is a solid-state additive manufacturing technique with potential for fabricating large-scale aluminum alloy structures while avoiding melting–solidification. In this study, a multifactorial design was used to identify an optimal parameter set for AA6061, and a ten-layer block was fabricated for microstructure/precipitate characterization and mechanical evaluation. Results indicate that the optimal parameters are 500 rpm and 120 mm/min. The deposit exhibits a fully refined equiaxed-grain structure with an average grain size of 5–8 μm, together with pronounced dislocation multiplication. Fine Al(MnCrFe)Si particles are dispersed in grain interiors, while coarsened β (Mg₂Si) precipitates are present along grain boundaries and within grains. The multilayer block shows a hardness range of 42.5–69.6 HV0.1 and near-isotropic tensile properties among BD/LD/TD, with UTS = 219.6 ± 5.0 MPa and elongation = 21.85 ± 2.71% along BD. These results provide a processing-window reference for dimensionally reliable AFSD build-up and repair of AA6061 components requiring low defect sensitivity and near-isotropic performance.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116090"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190497","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 : 2026-01-29DOI: 10.1016/j.matchar.2026.116085
Ales Buyakov, Marianna Lukyanets, Vasiliy Shmakov, Svetlana Buyakova
The effect of low–modulus hexagonal boron nitride (h-BN) content on the fracture toughness and abrasive wear resistance of ceramic composites ZrB2–TiB2–SiC (ZT series) and ZrB2–NbB2–SiC (ZN series) has been studied. The phase composition analysis of the synthesized ceramics revealed the formation of solid solutions (ZrxTi1-x)B2 and (ZrxNb1-x)B2. It was found that the introduction of h-BN into the ZT matrix did not significantly affect the stoichiometry of (Zr0.83Ti0.17)B2 and led to an increase in the fracture toughness of the composites with 5 vol%to 6.01 ± 0.09, MPa times m^{−1/2} due to the Cook-Gordon mechanism and crack arrest in residual compressive stress fields. The introduction of h-BN into ZN composites prevents complete involvement of ZrB2 in the formation of the (Zr,Nb)B2 solid solution, which leads to a decrease in the fracture toughness of the composites. The introduction of up to 5 vol% h-BN reduced the fracture toughness of ZN composites from 5.51 ± 0.08 to 4.42 ± 0.07, MPa times m^{−1/2}, compared to the fracture toughness of a ZN composite that did not contain h-BN. The measured coefficient of thermal expansion of (Zr0.72Nb0.28)B2 along the a- and c-axis directions are 7.24 times 10^{−6}, K^{−1} and 8.74 times 10^{−6}, K^{−1}, which indicates that the decrease in fracture toughness of ZN composites is due to crack development in tensile residual stress fields formed in the matrix near ZrB2 grains. It is shown that abrasive wear of ZT and ZN composites occurs due to the formation of subsurface microcracks.
{"title":"Effect of h-BN on the phase composition and mechanical properties of ZrB2–TiB2–SiC and ZrB2–NbB2–SiC composites","authors":"Ales Buyakov, Marianna Lukyanets, Vasiliy Shmakov, Svetlana Buyakova","doi":"10.1016/j.matchar.2026.116085","DOIUrl":"10.1016/j.matchar.2026.116085","url":null,"abstract":"<div><div>The effect of low–modulus hexagonal boron nitride (<em>h</em>-BN) content on the fracture toughness and abrasive wear resistance of ceramic composites ZrB<sub>2</sub>–TiB<sub>2</sub>–SiC (ZT series) and ZrB<sub>2</sub>–NbB<sub>2</sub>–SiC (ZN series) has been studied. The phase composition analysis of the synthesized ceramics revealed the formation of solid solutions (Zr<sub>x</sub>Ti<sub>1-x</sub>)B<sub>2</sub> and (Zr<sub>x</sub>Nb<sub>1-x</sub>)B<sub>2</sub>. It was found that the introduction of <em>h</em>-BN into the ZT matrix did not significantly affect the stoichiometry of (Zr<sub>0.83</sub>Ti<sub>0.17</sub>)B<sub>2</sub> and led to an increase in the fracture toughness of the composites with 5 vol%to 6.01 ± 0.09, MPa times m^{−1/2} due to the Cook-Gordon mechanism and crack arrest in residual compressive stress fields. The introduction of <em>h</em>-BN into ZN composites prevents complete involvement of ZrB<sub>2</sub> in the formation of the (Zr,Nb)B<sub>2</sub> solid solution, which leads to a decrease in the fracture toughness of the composites. The introduction of up to 5 vol% <em>h</em>-BN reduced the fracture toughness of ZN composites from 5.51 ± 0.08 to 4.42 ± 0.07, MPa times m^{−1/2}, compared to the fracture toughness of a ZN composite that did not contain <em>h</em>-BN. The measured coefficient of thermal expansion of (Zr<sub>0.72</sub>Nb<sub>0.28</sub>)B<sub>2</sub> along the <em>a</em>- and <em>c</em>-axis directions are 7.24 times 10^{−6}, K^{−1} and 8.74 times 10^{−6}, K^{−1}, which indicates that the decrease in fracture toughness of ZN composites is due to crack development in tensile residual stress fields formed in the matrix near ZrB<sub>2</sub> grains. It is shown that abrasive wear of ZT and ZN composites occurs due to the formation of subsurface microcracks.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116085"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189919","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 : 2026-01-29DOI: 10.1016/j.matchar.2026.116097
Shuai Gong , Baosheng Zhang , Peng He , Shuhai Chen , Zhimin Liang , Jihua Huang , Jian Yang
Aluminum (Al)/steel friction stir lap welding (FSLW) in which the tool pin does not penetrate the bottom steel substrate has recently received increasing attention. However, current research on this specific FSLW method still has many gaps, particularly in aspects such as temperature and material flow. This paper introduces the concept of a “viscous layer” into this specific FSLW method. It also discusses the effects of pin shape and rotational speed on the interfacial microstructure and joint properties. The results indicate that when the conical pin was used, a discontinuous intermetallic compound (IMC) layer formed at the interface. Compared to the continuous IMC layer formed by the cylindrical pin, the joint strength showed a moderate improvement. Then, we employed numerical simulation techniques to investigate the influence of the pin shape on the temperature distribution and material flow within the viscous layer. It was found that compared to the results obtained with the cylindrical pin, the use of the conical pin resulted in lower temperatures and more intense material flow within the viscous layer. Lower temperature and higher material flow velocity suppress atomic diffusion at the interface, leading to the formation of a discontinuous IMC layer. This indicates that temperature and material flow within the viscous layer are related to the interfacial microstructure.
{"title":"Effect of pin shape on interfacial microstructure and joint strength in friction stir lap welding with a retained viscous layer","authors":"Shuai Gong , Baosheng Zhang , Peng He , Shuhai Chen , Zhimin Liang , Jihua Huang , Jian Yang","doi":"10.1016/j.matchar.2026.116097","DOIUrl":"10.1016/j.matchar.2026.116097","url":null,"abstract":"<div><div>Aluminum (Al)/steel friction stir lap welding (FSLW) in which the tool pin does not penetrate the bottom steel substrate has recently received increasing attention. However, current research on this specific FSLW method still has many gaps, particularly in aspects such as temperature and material flow. This paper introduces the concept of a “viscous layer” into this specific FSLW method. It also discusses the effects of pin shape and rotational speed on the interfacial microstructure and joint properties. The results indicate that when the conical pin was used, a discontinuous intermetallic compound (IMC) layer formed at the interface. Compared to the continuous IMC layer formed by the cylindrical pin, the joint strength showed a moderate improvement. Then, we employed numerical simulation techniques to investigate the influence of the pin shape on the temperature distribution and material flow within the viscous layer. It was found that compared to the results obtained with the cylindrical pin, the use of the conical pin resulted in lower temperatures and more intense material flow within the viscous layer. Lower temperature and higher material flow velocity suppress atomic diffusion at the interface, leading to the formation of a discontinuous IMC layer. This indicates that temperature and material flow within the viscous layer are related to the interfacial microstructure.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116097"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189923","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 : 2026-01-29DOI: 10.1016/j.matchar.2026.116087
Kibeom Kim, Haoran Xie, Kwangil Seo, Yoko Yamabe-Mitarai
The development of two-phase microstructures analogous to the γ/γ' structure in Ni-based superalloys has rarely been achieved in refractory high-entropy alloys (RHEAs). In this study, Ti2AlMo-based multi-principal element alloys alloyed with V, Cr, Nb, and Ta were systematically designed to explore phase separation behavior and identify the key elements promoting A2 (disordered BCC) + Ordered B2 structures. Among all investigated compositions, only the Ta20 alloy exhibited a distinct A2 + B2 two-phase microstructure with cuboidal morphology-reported here for the first time in a Ti2AlMo-based system. TEM–EDS analysis confirmed that the cuboidal A2 precipitates were formed within an ordered-B2 matrix through spinodal decomposition, resembling the γ/γ' configuration in Ni-based superalloys. This unique microstructure significantly enhanced the high-temperature strength above 1073 K, while the B2 intermetallic matrix limited ductility. The Ta20 alloy represents a unique realization of a γ/γ'-like cuboidal A2 + B2 structure in a refractory alloy system, offering a promising design route toward next-generation high-temperature materials with balanced strength and ductility.
{"title":"Influence of BCC (A2)-structured elements on Ti2AlMo (B2) for the formation of A2 + B2 structure","authors":"Kibeom Kim, Haoran Xie, Kwangil Seo, Yoko Yamabe-Mitarai","doi":"10.1016/j.matchar.2026.116087","DOIUrl":"10.1016/j.matchar.2026.116087","url":null,"abstract":"<div><div>The development of two-phase microstructures analogous to the γ/γ' structure in Ni-based superalloys has rarely been achieved in refractory high-entropy alloys (RHEAs). In this study, Ti<sub>2</sub>AlMo-based multi-principal element alloys alloyed with V, Cr, Nb, and Ta were systematically designed to explore phase separation behavior and identify the key elements promoting A2 (disordered BCC) + Ordered B2 structures. Among all investigated compositions, only the Ta20 alloy exhibited a distinct A2 + B2 two-phase microstructure with cuboidal morphology-reported here for the first time in a Ti<sub>2</sub>AlMo-based system. TEM–EDS analysis confirmed that the cuboidal A2 precipitates were formed within an ordered-B2 matrix through spinodal decomposition, resembling the γ/γ' configuration in Ni-based superalloys. This unique microstructure significantly enhanced the high-temperature strength above 1073 K, while the B2 intermetallic matrix limited ductility. The Ta20 alloy represents a unique realization of a γ/γ'-like cuboidal A2 + B2 structure in a refractory alloy system, offering a promising design route toward next-generation high-temperature materials with balanced strength and ductility.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116087"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189920","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 : 2026-01-29DOI: 10.1016/j.matchar.2026.116081
Minqi Wang , Yihui Jiang , Ruonan Li , Siying Mao , Chunyang Zhu , Fei Cao , Yanfang Wang , Wenhao Yang , Zexin Wang , Shuhua Liang
Elucidating the in-situ reaction mechanism is essential for achieving the controllable fabrication of high-performance TiB2/Cu composites via powder metallurgy. However, the diffusion and reaction kinetics of elements within the Cu-Ti-B ternary system remain unclear. In this study, the diffusion couple method was employed to investigate the solid-state diffusion behavior and reaction mechanisms of Ti and B in Cu-based alloys. The results indicate that B diffusion dominates the reaction process, with the reaction layer forming exclusively on the Cu-Ti alloy side. The diffusion activation energy of B was determined to be 220.16 kJ/mol based on kinetics analysis of the reaction layer growth. According to the diffusion couple revealed diffusion reaction mechanism, a uniformly dispersed TiB2/Cu composite was fabricated through vibratory powder mixing followed by sintering. The microstructure evolution mechanism from powder contact, interface reaction to the homogenization of the reinforcement during the sintering process of the Cu-Ti-B ternary system was proposed.
{"title":"In-situ formation of TiB2 particles reinforced copper matrix composites via solid-state diffusion reaction","authors":"Minqi Wang , Yihui Jiang , Ruonan Li , Siying Mao , Chunyang Zhu , Fei Cao , Yanfang Wang , Wenhao Yang , Zexin Wang , Shuhua Liang","doi":"10.1016/j.matchar.2026.116081","DOIUrl":"10.1016/j.matchar.2026.116081","url":null,"abstract":"<div><div>Elucidating the in-situ reaction mechanism is essential for achieving the controllable fabrication of high-performance TiB<sub>2</sub>/Cu composites via powder metallurgy. However, the diffusion and reaction kinetics of elements within the Cu-Ti-B ternary system remain unclear. In this study, the diffusion couple method was employed to investigate the solid-state diffusion behavior and reaction mechanisms of Ti and B in Cu-based alloys. The results indicate that B diffusion dominates the reaction process, with the reaction layer forming exclusively on the Cu-Ti alloy side. The diffusion activation energy of B was determined to be 220.16 kJ/mol based on kinetics analysis of the reaction layer growth. According to the diffusion couple revealed diffusion reaction mechanism, a uniformly dispersed TiB<sub>2</sub>/Cu composite was fabricated through vibratory powder mixing followed by sintering. The microstructure evolution mechanism from powder contact, interface reaction to the homogenization of the reinforcement during the sintering process of the Cu-Ti-B ternary system was proposed.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116081"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189869","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 : 2026-01-29DOI: 10.1016/j.matchar.2026.116096
Yujin Aoyama , Shun Tokita , Kiyoaki T. Suzuki , Yuji Sutou , Yutaka S. Sato
AlN was brazed to Cu using Ag–29.5Cu–3Sn–1.5Ti filler sheets at various brazing temperatures and holding times. The brazeability of the filler sheet was investigated using constant-depth mode scanning acoustic microscopy analysis and cross-sectional observation. The microstructural evolution was clarified through detailed analyses using scanning electron microscopy and transmission electron microscopy. In particular, the reaction phase formed at the filler/AlN brazed interface was analyzed using electron energy-loss spectroscopy which is suitable for analyzing Ti–N compounds. The experimental results indicated that the brazeability of the filler improved at higher brazing temperatures. Defect-free interface was achieved at brazing temperatures of 1123 K and 1173 K. In addition, interdiffusion between Cu and the filler was observed. A coarse granular τ1-CuTi5Sn3 and a fine crystalline NaCl-type TiN were observed at the filler and AlN brazed interface, suggesting that the brazing was achieved by formation of TiN through the reaction between Ti in the filler and AlN.
{"title":"Microstructure evolution during Cu/AlN vacuum brazing using Ag–29.5Cu–3Sn–1.5Ti filler sheet: electron energy-loss spectroscopic study","authors":"Yujin Aoyama , Shun Tokita , Kiyoaki T. Suzuki , Yuji Sutou , Yutaka S. Sato","doi":"10.1016/j.matchar.2026.116096","DOIUrl":"10.1016/j.matchar.2026.116096","url":null,"abstract":"<div><div>AlN was brazed to Cu using Ag–29.5Cu–3Sn–1.5Ti filler sheets at various brazing temperatures and holding times. The brazeability of the filler sheet was investigated using constant-depth mode scanning acoustic microscopy analysis and cross-sectional observation. The microstructural evolution was clarified through detailed analyses using scanning electron microscopy and transmission electron microscopy. In particular, the reaction phase formed at the filler/AlN brazed interface was analyzed using electron energy-loss spectroscopy which is suitable for analyzing Ti–N compounds. The experimental results indicated that the brazeability of the filler improved at higher brazing temperatures. Defect-free interface was achieved at brazing temperatures of 1123 K and 1173 K. In addition, interdiffusion between Cu and the filler was observed. A coarse granular τ<sub>1</sub>-CuTi<sub>5</sub>Sn<sub>3</sub> and a fine crystalline NaCl-type TiN were observed at the filler and AlN brazed interface, suggesting that the brazing was achieved by formation of TiN through the reaction between Ti in the filler and AlN.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116096"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189921","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 : 2026-01-29DOI: 10.1016/j.matchar.2026.116084
Esam Alqadhi , Hongxiang Jiang , Muhammad Ali , Binghao Han , Lili Zhang , Jiuzhou Zhao , Jie He
The solidification of immiscible alloys has been extensively researched for decades due to their ability to provide a wide range of advantageous properties. This study investigates the effect of the microalloying element La on the solidification behavior, microstructure, as well as the mechanical and wear characteristics of as-cast hypomonotectic Cu-Pb-Sn alloys. The findings reveal that an optimal addition of La (∼0.06 wt%) enhances the ultimate tensile strength, yield strength, elongation, and wear resistance of the alloy. This improvement is attributed to the simultaneous refinement of the α-Cu matrix grain size and the Pb-rich secondary phase particles (SPPs). However, when the La content reaches or exceeds 0.10 wt%, it leads to the precipitation of La₅Pb₃ and LaSn intermetallic compounds, which have hexagonal and orthorhombic structures, respectively, and thus negatively affect the mechanical properties and wear resistance. The mechanism of La on the solidification process of Cu-10Pb-10Sn alloys was analyzed. The results confirm that La effectively reduces the interfacial tension between the two liquid phases during liquid-liquid (L-L) decomposition, thereby enhancing the nucleation rate of Pb-rich secondary phase droplets and promoting the formation of Cu-Pb-Sn alloys with a well-dispersed microstructure. Furthermore, La reduces the wetting angle (θ) between the nucleation substrate and α-Cu, which enhances α-Cu nucleation and refines the matrix grains.
{"title":"Simultaneous refinement of matrix grains and Pb-rich phases in hypomonotectic Cu-10Pb-10Sn alloys via La microalloying for enhanced strength and wear resistance","authors":"Esam Alqadhi , Hongxiang Jiang , Muhammad Ali , Binghao Han , Lili Zhang , Jiuzhou Zhao , Jie He","doi":"10.1016/j.matchar.2026.116084","DOIUrl":"10.1016/j.matchar.2026.116084","url":null,"abstract":"<div><div>The solidification of immiscible alloys has been extensively researched for decades due to their ability to provide a wide range of advantageous properties. This study investigates the effect of the microalloying element La on the solidification behavior, microstructure, as well as the mechanical and wear characteristics of as-cast hypomonotectic Cu-Pb-Sn alloys. The findings reveal that an optimal addition of La (∼0.06 wt%) enhances the ultimate tensile strength, yield strength, elongation, and wear resistance of the alloy. This improvement is attributed to the simultaneous refinement of the α-Cu matrix grain size and the Pb-rich secondary phase particles (SPPs). However, when the La content reaches or exceeds 0.10 wt%, it leads to the precipitation of La₅Pb₃ and LaSn intermetallic compounds, which have hexagonal and orthorhombic structures, respectively, and thus negatively affect the mechanical properties and wear resistance. The mechanism of La on the solidification process of Cu-10Pb-10Sn alloys was analyzed. The results confirm that La effectively reduces the interfacial tension between the two liquid phases during liquid-liquid (L-L) decomposition, thereby enhancing the nucleation rate of Pb-rich secondary phase droplets and promoting the formation of Cu-Pb-Sn alloys with a well-dispersed microstructure. Furthermore, La reduces the wetting angle (θ) between the nucleation substrate and α-Cu, which enhances α-Cu nucleation and refines the matrix grains.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116084"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189873","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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