Pub Date : 2026-01-24DOI: 10.1016/j.matchar.2026.116049
Yuanjie Chi , Fei Ji , Hui Chen, Yuanxing Li
This study investigates the strengthening effects and underlying mechanisms of brazed Ti6Al4V/bismuth-based sealing glass/ZrO2 joints by comparing two surface pretreatment methods: thermal oxidation and laser surface treatment. Ti6Al4V and ZrO2 ceramic brazing connections are widely used in electronic packaging, fuel cells, and other fields. Sealing glass selected as brazing filler for joining. However, the poor wettability between titanium alloy and glass requires surface pretreatment to improve bonding. Experiments show that the joint strength after laser treatment reached 46 MPa, significantly higher than the 35 MPa obtained by thermal oxidation. Interfacial analysis reveals that thermal oxidation primarily achieves bonding through elemental interdiffusion and chemical reactions. In contrast, laser treatment not only facilitates elemental diffusion and chemical reactions, but also induces the precipitation of Bi spherical particles, resulting in a dispersion strengthening effect. Simultaneously, brazing filler infiltrates laser-generated pits to form mechanical interlocking structures, synergizing chemical and mechanical reinforcement.
{"title":"Strengthening mechanisms and performance enhancement of laser surface treatment on Ti6Al4V/glass/ZrO2 brazed joints","authors":"Yuanjie Chi , Fei Ji , Hui Chen, Yuanxing Li","doi":"10.1016/j.matchar.2026.116049","DOIUrl":"10.1016/j.matchar.2026.116049","url":null,"abstract":"<div><div>This study investigates the strengthening effects and underlying mechanisms of brazed Ti6Al4V/bismuth-based sealing glass/ZrO<sub>2</sub> joints by comparing two surface pretreatment methods: thermal oxidation and laser surface treatment. Ti6Al4V and ZrO<sub>2</sub> ceramic brazing connections are widely used in electronic packaging, fuel cells, and other fields. Sealing glass selected as brazing filler for joining. However, the poor wettability between titanium alloy and glass requires surface pretreatment to improve bonding. Experiments show that the joint strength after laser treatment reached 46 MPa, significantly higher than the 35 MPa obtained by thermal oxidation. Interfacial analysis reveals that thermal oxidation primarily achieves bonding through elemental interdiffusion and chemical reactions. In contrast, laser treatment not only facilitates elemental diffusion and chemical reactions, but also induces the precipitation of Bi spherical particles, resulting in a dispersion strengthening effect. Simultaneously, brazing filler infiltrates laser-generated pits to form mechanical interlocking structures, synergizing chemical and mechanical reinforcement.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116049"},"PeriodicalIF":5.5,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090605","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 : 2026-01-24DOI: 10.1016/j.matchar.2026.116044
A. Fedoseeva , A. Dolzhenko , A. Klauz , А. Khalyavina , R. Kaibyshev
{"title":"Creep behavior and microstructural degradation of advanced 12% Cr-3% Co steel with low N and high B contents during creep at various elevated temperatures","authors":"A. Fedoseeva , A. Dolzhenko , A. Klauz , А. Khalyavina , R. Kaibyshev","doi":"10.1016/j.matchar.2026.116044","DOIUrl":"10.1016/j.matchar.2026.116044","url":null,"abstract":"","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116044"},"PeriodicalIF":5.5,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090587","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 : 2026-01-24DOI: 10.1016/j.matchar.2026.116046
Liming Tan , Zi Wang , Yongan Gui , Jiahao Tu , Lan Huang , Weifu Li , Yong Liu , Feng Liu
Image recognition technology has demonstrated significant potential and application value in materials science. However, current image recognition technologies still face bottlenecks like poor adaptability to complex images and sensitivity to noise when dealing with intricate imagery. To address these challenges, we developed a novel approach that integrates Convolutional Neural Networks with Transformer encoders. This method not only handles multi-class tissue segmentation tasks but also performs phase recognition at various scales, showcasing its broad applicability and powerful functionality. This research advances the development of microstructure image segmentation technology and provides a potent tool for microstructure analysis in materials science.
{"title":"Revolutionizing multi-scale phase identification in superalloys via advanced CNN-transformer integration","authors":"Liming Tan , Zi Wang , Yongan Gui , Jiahao Tu , Lan Huang , Weifu Li , Yong Liu , Feng Liu","doi":"10.1016/j.matchar.2026.116046","DOIUrl":"10.1016/j.matchar.2026.116046","url":null,"abstract":"<div><div>Image recognition technology has demonstrated significant potential and application value in materials science. However, current image recognition technologies still face bottlenecks like poor adaptability to complex images and sensitivity to noise when dealing with intricate imagery. To address these challenges, we developed a novel approach that integrates Convolutional Neural Networks with Transformer encoders. This method not only handles multi-class tissue segmentation tasks but also performs phase recognition at various scales, showcasing its broad applicability and powerful functionality. This research advances the development of microstructure image segmentation technology and provides a potent tool for microstructure analysis in materials science.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116046"},"PeriodicalIF":5.5,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090586","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 : 2026-01-23DOI: 10.1016/j.matchar.2026.116069
Yue Li , Shuai Long , Quan Gan , Rui-bo Du , Peng Peng , Cheng Zhang , Xin Wan , Shu-yan Wang , Juan Yu , Jie Zhou
In high-strength 7xxx Al alloys, post-solution pre-strain is widely used to reduce quenching-induced residual stresses, yet its combined effects on mechanical and corrosion properties remain unclear. Here, a solution-treated 7085 alloy was subjected to equivalent pre-strains (ε) of 0, 0.032, 0.067, and 0.104, followed by aging treatment. Microstructural characterization by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) and property testing were performed. The unstrained condition showed continuous grain-boundary precipitates (GBPs) and sparse intragranular η' particles, leading to moderate strength and poor corrosion resistance, with a corrosion current density (Icorr) of 2.63 × 10−6 A·cm−2. At a moderate pre-strain of ε = 0.032, the yield strength (YS) increased from 468 MPa to 516 MPa, while the elongation (EL) decreased from 16.8% to 14.6%. Meanwhile, the Icorr was reduced to 9.66 × 10−7 A·cm−2. This improvement is associated with an increased dislocation density, which promotes fine and uniform η' precipitation, discontinuous Cu-enriched GBPs, and an optimized precipitation-free zone (PFZ) width. At higher pre-strain, GBPs became coarse, the PFZ widened, and η' → η transformation was accelerated, accompanied by the presence of minor Al₃Zr dispersoids. Consequently, the YS decreased to 469 MPa (EL 15.47%), and the Icorr increased to 6.42 × 10−6 A·cm−2. Strength analysis indicates that although dislocation strengthening increases with pre-strain, precipitation hardening is significantly weakened, resulting in a net strength decline. Overall, an optimal pre-strain enables dislocation-assisted precipitation control and achieves a favorable balance between mechanical properties and corrosion resistance.
{"title":"Synergistic enhancement of strength and corrosion resistance in a high-strength 7xxx Al alloy via pre-strain-mediated precipitation control","authors":"Yue Li , Shuai Long , Quan Gan , Rui-bo Du , Peng Peng , Cheng Zhang , Xin Wan , Shu-yan Wang , Juan Yu , Jie Zhou","doi":"10.1016/j.matchar.2026.116069","DOIUrl":"10.1016/j.matchar.2026.116069","url":null,"abstract":"<div><div>In high-strength 7xxx Al alloys, post-solution pre-strain is widely used to reduce quenching-induced residual stresses, yet its combined effects on mechanical and corrosion properties remain unclear. Here, a solution-treated 7085 alloy was subjected to equivalent pre-strains (ε) of 0, 0.032, 0.067, and 0.104, followed by aging treatment. Microstructural characterization by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) and property testing were performed. The unstrained condition showed continuous grain-boundary precipitates (GBPs) and sparse intragranular η' particles, leading to moderate strength and poor corrosion resistance, with a corrosion current density (I<sub>corr</sub>) of 2.63 × 10<sup>−6</sup> A·cm<sup>−2</sup>. At a moderate pre-strain of ε = 0.032, the yield strength (YS) increased from 468 MPa to 516 MPa, while the elongation (EL) decreased from 16.8% to 14.6%. Meanwhile, the I<sub>corr</sub> was reduced to 9.66 × 10<sup>−7</sup> A·cm<sup>−2</sup>. This improvement is associated with an increased dislocation density, which promotes fine and uniform η' precipitation, discontinuous Cu-enriched GBPs, and an optimized precipitation-free zone (PFZ) width. At higher pre-strain, GBPs became coarse, the PFZ widened, and η' → η transformation was accelerated, accompanied by the presence of minor Al₃Zr dispersoids. Consequently, the YS decreased to 469 MPa (EL 15.47%), and the I<sub>corr</sub> increased to 6.42 × 10<sup>−6</sup> A·cm<sup>−2</sup>. Strength analysis indicates that although dislocation strengthening increases with pre-strain, precipitation hardening is significantly weakened, resulting in a net strength decline. Overall, an optimal pre-strain enables dislocation-assisted precipitation control and achieves a favorable balance between mechanical properties and corrosion resistance.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116069"},"PeriodicalIF":5.5,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090518","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 : 2026-01-23DOI: 10.1016/j.matchar.2026.116068
Qifeng Cai , Zhilong Chang , Yan Liu , Peng Ren , Zhihao Zhang , Zijie Zhang , Weicheng Zhang , Geng Cao , Hua Zhang
Friction stir welding (FSW) is an effective technique for joining dissimilar aluminum alloys, while the microstructural heterogeneity introduced by FSW has a significant impact on the corrosion performance of the joints. In this study, systematic microstructural characterization and corrosion experiments were conducted to investigate the microstructural features and localized corrosion behavior of seven representative regions within the weld zone (WZ) and base metal (BM) of dissimilar 2195/2219 aluminum alloy joints. The results indicate that in the 2195 weld zone (5-WZ), coarsened Cu₃Al₂ and Al₂Cu phases are continuously distributed along grain boundaries, accompanied by a higher fraction of high-angle grain boundaries and dislocation density compared with the 2219 weld zone (9-WZ). Moreover, the 5-WZ exhibits a significantly higher Mg content but a relatively lower Cu content than the 9-WZ. During the intergranular corrosion stage, such microstructural heterogeneity reduces the overall resistance of the WZ to grain boundary corrosion, leading to the most severe attack at the bottom of the WZ. The synergistic effect of grain boundary corrosion and intergranular corrosion further accelerates material dissolution, resulting in obvious corrosion pits in the 5-WZ, whereas the 9-WZ remains almost unaffected. Electrochemical tests revealed that the corrosion resistance of the investigated regions decreases in the following order: 9-WZ > 5-WZ > shoulder interface zone (SIZ) > vortex zone (VZ) > bottom interface zone (BIZ) > 9-BM > 5-BM. This study elucidates the corrosion mechanism of dissimilar FSW joints from the perspective of microstructural heterogeneity.
{"title":"Effect of friction stir welding-induced heterogeneity on the localized corrosion behavior of 2195/2219 dissimilar Al alloy joints","authors":"Qifeng Cai , Zhilong Chang , Yan Liu , Peng Ren , Zhihao Zhang , Zijie Zhang , Weicheng Zhang , Geng Cao , Hua Zhang","doi":"10.1016/j.matchar.2026.116068","DOIUrl":"10.1016/j.matchar.2026.116068","url":null,"abstract":"<div><div>Friction stir welding (FSW) is an effective technique for joining dissimilar aluminum alloys, while the microstructural heterogeneity introduced by FSW has a significant impact on the corrosion performance of the joints. In this study, systematic microstructural characterization and corrosion experiments were conducted to investigate the microstructural features and localized corrosion behavior of seven representative regions within the weld zone (WZ) and base metal (BM) of dissimilar 2195/2219 aluminum alloy joints. The results indicate that in the 2195 weld zone (5-WZ), coarsened Cu₃Al₂ and Al₂Cu phases are continuously distributed along grain boundaries, accompanied by a higher fraction of high-angle grain boundaries and dislocation density compared with the 2219 weld zone (9-WZ). Moreover, the 5-WZ exhibits a significantly higher Mg content but a relatively lower Cu content than the 9-WZ. During the intergranular corrosion stage, such microstructural heterogeneity reduces the overall resistance of the WZ to grain boundary corrosion, leading to the most severe attack at the bottom of the WZ. The synergistic effect of grain boundary corrosion and intergranular corrosion further accelerates material dissolution, resulting in obvious corrosion pits in the 5-WZ, whereas the 9-WZ remains almost unaffected. Electrochemical tests revealed that the corrosion resistance of the investigated regions decreases in the following order: 9-WZ > 5-WZ > shoulder interface zone (SIZ) > vortex zone (VZ) > bottom interface zone (BIZ) > 9-BM > 5-BM. This study elucidates the corrosion mechanism of dissimilar FSW joints from the perspective of microstructural heterogeneity.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116068"},"PeriodicalIF":5.5,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The laser direct welding connection between sapphire and TC4 alloy was an important challenge in the fields of aerospace, electronic packaging. Through systematic research on the influence of interfacial pressure from 0 MPa to1.75 MPa on welding quality, it was found that pressure parameters significantly affect joint performance by regulating the triple mechanism of interface contact, element diffusion, and fracture mechanism. Under the action of the optimized interface pressure of 0.75 MPa, even in the practical working conditions where the welded parts are in non-optical contact and the metal surface roughness is as high as Rz 445 nm, the elimination of interface gaps, the promotion of Ti Al interdiffusion to form AlTi3 intermetallic compounds, and the effective balance between interface bonding and base metal integrity were achieved. The shear strength of the joint reached 32.0 MPa, and fracture analysis showed brittle mixed fracture characteristics under this condition. The research provided a novel solution for direct fusion welding of sapphire-metal heterostructures.
{"title":"Enhancement mechanism of shear strength in sapphire/TC4 alloy joints via femtosecond laser welding with interfacial pressure","authors":"Quanqi Zuo , Jian Qin , Weimin Long , Yuanxun Shen , Yue Zhao , Yongtao Jiu","doi":"10.1016/j.matchar.2026.116063","DOIUrl":"10.1016/j.matchar.2026.116063","url":null,"abstract":"<div><div>The laser direct welding connection between sapphire and TC4 alloy was an important challenge in the fields of aerospace, electronic packaging. Through systematic research on the influence of interfacial pressure from 0 MPa to1.75 MPa on welding quality, it was found that pressure parameters significantly affect joint performance by regulating the triple mechanism of interface contact, element diffusion, and fracture mechanism. Under the action of the optimized interface pressure of 0.75 MPa, even in the practical working conditions where the welded parts are in non-optical contact and the metal surface roughness is as high as Rz 445 nm, the elimination of interface gaps, the promotion of Ti Al interdiffusion to form AlTi<sub>3</sub> intermetallic compounds, and the effective balance between interface bonding and base metal integrity were achieved. The shear strength of the joint reached 32.0 MPa, and fracture analysis showed brittle mixed fracture characteristics under this condition. The research provided a novel solution for direct fusion welding of sapphire-metal heterostructures.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116063"},"PeriodicalIF":5.5,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090519","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 : 2026-01-22DOI: 10.1016/j.matchar.2026.116041
Seyed Moien Faregh , Daniel Larouche , X. Grant Chen , François Nadeau
The precipitation sequence during continuous heating in a Mg-rich AlMgSi alloy containing minor additions of Cu is investigated. Differential scanning calorimetry (DSC) curves were acquired for wrought Al1.01 Mg0.61Si0.25Cu (wt%) specimens and the resulting peaks were studied using scanning transmission electron microscopy (STEM), atom probe tomography (APT) and hardness measurements to clarify the sequence of metastable phase precipitation. APT results indicated that the first exothermic reaction is dominated by the formation of Mg-Si co-clusters enriched in Mg. High-resolution TEM revealed that the initial Mg-Si precipitates are Guinier-Preston (GP) zones, with the peak of the first exotherm corresponding to an increase in their number density. STEM lattice imaging confirmed that these GP zones exhibit a single β′′-eye structure. Analysis of the second exotherm showed that its onset belongs predominantly to precipitation of L phases while its peak is related to formation of precipitates. Measurements showed that the continuous heating of the alloy from an as-quenched state to the peak of the first exotherm leads to a hardness increase from 61 HV to 98 HV, making the GP zones responsible for the hardening of the alloy under these tempering conditions.
{"title":"On the precipitation kinetics of a wrought 6061 alloy during continuous heating","authors":"Seyed Moien Faregh , Daniel Larouche , X. Grant Chen , François Nadeau","doi":"10.1016/j.matchar.2026.116041","DOIUrl":"10.1016/j.matchar.2026.116041","url":null,"abstract":"<div><div>The precipitation sequence during continuous heating in a Mg-rich AlMgSi alloy containing minor additions of Cu is investigated. Differential scanning calorimetry (DSC) curves were acquired for wrought Al1.01 Mg0.61Si0.25Cu (wt%) specimens and the resulting peaks were studied using scanning transmission electron microscopy (STEM), atom probe tomography (APT) and hardness measurements to clarify the sequence of metastable phase precipitation. APT results indicated that the first exothermic reaction is dominated by the formation of Mg-Si co-clusters enriched in Mg. High-resolution TEM revealed that the initial Mg-Si precipitates are Guinier-Preston (GP) zones, with the peak of the first exotherm corresponding to an increase in their number density. STEM lattice imaging confirmed that these GP zones exhibit a single <em>β</em>′′-eye structure. Analysis of the second exotherm showed that its onset belongs predominantly to precipitation of L phases while its peak is related to formation of <span><math><msubsup><mi>β</mi><mi>Cu</mi><mo>′</mo></msubsup></math></span> precipitates. Measurements showed that the continuous heating of the alloy from an as-quenched state to the peak of the first exotherm leads to a hardness increase from 61 HV to 98 HV, making the GP zones responsible for the hardening of the alloy under these tempering conditions.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116041"},"PeriodicalIF":5.5,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036777","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 : 2026-01-22DOI: 10.1016/j.matchar.2026.116028
Chang-Yeon Kim , Jin-Gyu Kim , Min-Gi Jeon , Artavazd Kirakosyan , Subin Yun , Sang-Gil Lee , Heejin Kim , Ji-Hyun Lee , Kyubin Shim , Li Li , Hae Jin Kim , Jihoon Choi
Metal halide perovskite (MHP) nanowires (NWs) have recently attracted considerable attention owing to their tunable optical properties and promising potential for integration into advanced optoelectronic devices. However, a comprehensive understanding of how ligand chemistry governs facet formation, grain boundary evolution, and structural chirality in MHP NWs is still lacking. Here, we systematically investigate the role of ligand architecture on the crystallographic and morphological evolution of CsPbBr3 NWs, employing high-resolution transmission electron microscopy, tomography, and automated crystal orientation mapping. Our results reveal that the preferential stabilization of low-index facets ({100}, {010}, {001}) lowers surface energies and promotes structural stability, while the formation of Σ3 coincidence site lattice grain boundaries minimizes grain boundary energy and enables preferred longitudinal orientations along the 〈201〉 and 〈021〉 directions. Chiral aromatic amines (S−/R-1-(1-naphthyl) ethylamine) selectively stabilized low-energy facets, leading to the formation of cube-connected NWs. In contrast, oleylamine stabilized both low- and high-index facets, including {101}, inducing helical morphologies and the associated chirality. The CD signal of the CsPbBr3 NWs depending on their chirality confirms strong electronic coupling between the chiral ligands and the CsPbBr3 NWs. These findings establish a mechanistic framework for ligand-directed facet engineering and chirality control in perovskite NWs, providing a strategic pathway for designing polarization-sensitive and high-performance optoelectronic materials.
{"title":"Ligand-directed facet stabilization in chiral CsPbBr3 nanowires","authors":"Chang-Yeon Kim , Jin-Gyu Kim , Min-Gi Jeon , Artavazd Kirakosyan , Subin Yun , Sang-Gil Lee , Heejin Kim , Ji-Hyun Lee , Kyubin Shim , Li Li , Hae Jin Kim , Jihoon Choi","doi":"10.1016/j.matchar.2026.116028","DOIUrl":"10.1016/j.matchar.2026.116028","url":null,"abstract":"<div><div>Metal halide perovskite (MHP) nanowires (NWs) have recently attracted considerable attention owing to their tunable optical properties and promising potential for integration into advanced optoelectronic devices. However, a comprehensive understanding of how ligand chemistry governs facet formation, grain boundary evolution, and structural chirality in MHP NWs is still lacking. Here, we systematically investigate the role of ligand architecture on the crystallographic and morphological evolution of CsPbBr<sub>3</sub> NWs, employing high-resolution transmission electron microscopy, tomography, and automated crystal orientation mapping. Our results reveal that the preferential stabilization of low-index facets ({100}, {010}, {001}) lowers surface energies and promotes structural stability, while the formation of Σ3 coincidence site lattice grain boundaries minimizes grain boundary energy and enables preferred longitudinal orientations along the 〈201〉 and 〈021〉 directions. Chiral aromatic amines (S−/R-1-(1-naphthyl) ethylamine) selectively stabilized low-energy facets, leading to the formation of cube-connected NWs. In contrast, oleylamine stabilized both low- and high-index facets, including {101}, inducing helical morphologies and the associated chirality. The CD signal of the CsPbBr<sub>3</sub> NWs depending on their chirality confirms strong electronic coupling between the chiral ligands and the CsPbBr<sub>3</sub> NWs. These findings establish a mechanistic framework for ligand-directed facet engineering and chirality control in perovskite NWs, providing a strategic pathway for designing polarization-sensitive and high-performance optoelectronic materials.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116028"},"PeriodicalIF":5.5,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090596","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 : 2026-01-22DOI: 10.1016/j.matchar.2026.116045
You Zhou , Zhiyan Zhang , Xuewei Fang , Zhenhuan Gao , Hongkai Zhang , Yanyao Xu , Liping Nie , Yufan Liu , Jiarong Guo , Ke Huang
In this work, the wrought 34CrNiMo6 steel has been repaired by the laser directed energy deposition and then heat treated by two different schemes: the quenching & tempering (QT) and the tempering (T). The cross-regional microstructure evolution has been examined by various characterization methods. The tensile and shear tests were conducted to evaluate the quality of the repaired samples. The results indicated that the inferior ductility and interfacial toughness of the as-repaired steel were due to the bainite and martensite within the deposition region and heat affected zone (HAZ). After the QT treatment, all heterogeneous microstructure has transformed to the tempered sorbite, which improves the ductility and interfacial toughness at the cost of slightly sacrificed strength. Furthermore, the T treatment can also soften the hard & brittle structures, thereby avoiding the premature failure. However, due to the lack of austenitization, the heterogeneous microstructure has also slightly deteriorated the ductility and toughness as compared to those of the QT treated repaired steels. This work provides new insights into tailoring the microstructure and mechanical properties of the repaired structural steels.
{"title":"Trade-off between strength, ductility and toughness of laser directed energy deposition repaired 34CrNiMo6 steel with different heat treatment schedules","authors":"You Zhou , Zhiyan Zhang , Xuewei Fang , Zhenhuan Gao , Hongkai Zhang , Yanyao Xu , Liping Nie , Yufan Liu , Jiarong Guo , Ke Huang","doi":"10.1016/j.matchar.2026.116045","DOIUrl":"10.1016/j.matchar.2026.116045","url":null,"abstract":"<div><div>In this work, the wrought 34CrNiMo6 steel has been repaired by the laser directed energy deposition and then heat treated by two different schemes: the quenching & tempering (QT) and the tempering (T). The cross-regional microstructure evolution has been examined by various characterization methods. The tensile and shear tests were conducted to evaluate the quality of the repaired samples. The results indicated that the inferior ductility and interfacial toughness of the as-repaired steel were due to the bainite and martensite within the deposition region and heat affected zone (HAZ). After the QT treatment, all heterogeneous microstructure has transformed to the tempered sorbite, which improves the ductility and interfacial toughness at the cost of slightly sacrificed strength. Furthermore, the T treatment can also soften the hard & brittle structures, thereby avoiding the premature failure. However, due to the lack of austenitization, the heterogeneous microstructure has also slightly deteriorated the ductility and toughness as compared to those of the QT treated repaired steels. This work provides new insights into tailoring the microstructure and mechanical properties of the repaired structural steels.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"233 ","pages":"Article 116045"},"PeriodicalIF":5.5,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090592","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 : 2026-01-21DOI: 10.1016/j.matchar.2026.116034
Ye Yuan , Yinsong Xie , Konghui Ma , Hong Liang , Zicheng Li , Yu Liu , Taisen Zuo , Zhaohui Dong , Hongying Yu , Dongbai Sun , Xin Xu
The microstructural evolution, mechanical response and corrosion behavior of a model super martensitic stainless steel (SMSS) Fe-13Cr-5Ni-3Cu tempered at 600 °C were systematically studied. A multiscale characterization approach combining synchrotron X-ray diffraction, small-angle neutron scattering, electron backscatter diffraction and transmission electron microscopy reveals the coupled evolution of Cu-rich precipitates (CRPs) and reversed austenite (RvA). CRPs exhibit sequential anisotropic growth, initially elongating along the long axis and subsequently coarsening along the short axis. Their number density and volume fraction peak at 1 h before declining with tempering time due to coarsening and coalescence. The interplay between CRPs and RvA governs the time-dependent mechanical and electrochemical properties of the alloy. Short-term tempering produces fine CRPs that maximize precipitation strengthening and strain hardening, yielding superior strength–ductility synergy, tensile strength of 868 MPa with 16% elongation for 1 h tempering, without sacrificing corrosion resistance. In contrast, prolonged tempering leads to CRP coarsening and RvA-induced softening, reduced strength and impaired pitting resistance. These results establish a clear process–microstructure–property relationship for Cu-bearing SMSSs, assisting the development of the next-generation SMSSs with optimized strength and corrosion resistance.
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