Elina Akbarzadeh Chiniforoush , Habib Hamed Zargari , Mohammad Reza Jandaghi , Johan Moverare , Reyazul Warsi , C. Hakan Gür
{"title":"A sustainable strategy for wire arc additive manufacturing of high-performance duplex stainless Steel: Microstructural refinement and mechanical anisotropy reduction","authors":"Elina Akbarzadeh Chiniforoush , Habib Hamed Zargari , Mohammad Reza Jandaghi , Johan Moverare , Reyazul Warsi , C. Hakan Gür","doi":"10.1016/j.msea.2025.148785","DOIUrl":"10.1016/j.msea.2025.148785","url":null,"abstract":"<div><div>A major challenge in wire arc additive manufacturing (WAAM) is microstructural anisotropy caused by columnar grain growth due to predominant heat transfer toward the substrate, which compromises mechanical performance. This study investigates the effectiveness of the switch-back (SB) welding strategy in reducing anisotropy and enhancing the mechanical properties of WAAM-fabricated duplex stainless steel (ER 2209). Two walls were fabricated using identical process parameters, differing only in torch movement: conventional (Norm) and SB paths. Microstructural analysis revealed a marked reduction in columnar grains and increased equiaxed grain fraction in the SB samples. EBSD IPF maps showed an 83 % and 70 % reduction in crystallographic alignment for δ-ferrite and γ-austenite, respectively. Numerical simulations demonstrated that the SB strategy generated higher peak temperatures and greater melt turbulence, reducing the G/R ratio and promoting dendrite fragmentation and equiaxed grain formation. Mechanical testing confirmed improved performance of SB samples, with SB-H achieving the highest UTS (816 MPa) and impact energy (74.7 J). Fractographic analysis revealed ductile failure in all samples, with SB samples exhibiting finer and more uniform dimples, indicating enhanced toughness. Overall, the switch-back strategy is a simple yet effective method for improving structural and mechanical performance in WAAM without requiring additional equipment.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"943 ","pages":"Article 148785"},"PeriodicalIF":6.1,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588353","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}
Wenqing Yang , Wenjie Lu , Lei Qian , Xu-Sheng Yang
{"title":"Achieving enhanced strength-ductility synergy in an additive manufactured eutectic compositionally complex alloy via optimizing alloy composition","authors":"Wenqing Yang , Wenjie Lu , Lei Qian , Xu-Sheng Yang","doi":"10.1016/j.msea.2025.148789","DOIUrl":"10.1016/j.msea.2025.148789","url":null,"abstract":"<div><div>Additive manufacturing of metallic materials creates structures layer-by-layer through rapid melting and solidification, which can promote refined microstructure and enhanced strength. This study investigates the impact of regulating Co content on microstructural evolution and mechanical properties in eutectic AlCoCrFeNi<sub>2.1</sub> compositionally complex alloy (CCA) fabricated through laser engineered net shaping technique. Our work clearly demonstrates that subtly regulating Co content can significantly manipulate the lamellar spacing and phase volume fraction, resulting in enhanced strength-ductility combination. Notably, compared with the original eutectic AlCoCrFeNi<sub>2.1</sub> CCA with a tensile strength at ∼883 MPa and fracture elongation at ∼11 %, our designed AlCo<sub>1.2</sub>CrFeNi<sub>2.1</sub> CCA with a higher Co content exhibits superior strength-ductility synergy, showing a remarkable tensile strength at ∼1602 MPa and fracture elongation at ∼14 %. This increased Co concentration promotes lamellar refinement and introduces more phase boundaries in the FCC/BCC dual-phase microstructure, which induce strengthening effect through dislocation pile-up at the phase boundaries. Meanwhile, the coherent interfaces between FCC and BCC facilitate dislocation propagation across the phase boundaries and support strain accommodation, ultimately achieving an exceptional strength-ductility balance. Our findings provide valuable insights for further design and rapid development of high-performance additive-manufactured alloys by adjusting the elemental composition.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"943 ","pages":"Article 148789"},"PeriodicalIF":6.1,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144605041","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}
Z. Wang , Z.Y. Wang , J.W. Qiao , M. Zhang , Pedro E.J. Rivera-Díaz-del-Castillo , Z.H. Wang
{"title":"Double yielding mechanisms in Ti48Zr30Ni6Ta1Al1Be14 metallic glass matrix composites","authors":"Z. Wang , Z.Y. Wang , J.W. Qiao , M. Zhang , Pedro E.J. Rivera-Díaz-del-Castillo , Z.H. Wang","doi":"10.1016/j.msea.2025.148779","DOIUrl":"10.1016/j.msea.2025.148779","url":null,"abstract":"<div><div>Ti-based metallic glass matrix composites (MGMCs) are composed of amorphous phase, <em>β</em> phase and <em>α</em> phase at room temperature. The stress-strain curve of the MGMCs exhibits a “double yield” phenomenon at room temperature, which disappears at low temperatures. The tensile deformation mechanism of the MGMC is deformation-induced martensitic transformation at 298 K and deformation twins at 77 K. The phase transformation starts from the dendrite boundaries, which will hinder the dislocation movement and further enhance the work hardening capability at room temperature. The stability of dendrites was evaluated by martensite trigger stress and critical <em>α</em> lath length, which provided guidance for exploring the deformation mechanism of amorphous composites.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"943 ","pages":"Article 148779"},"PeriodicalIF":6.1,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144604588","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}
{"title":"Core-shell strategy for triple-phase reinforced (Al2O3+SiC+Al3BC)/Al composite: Achieving enhanced stiffness and strength while retained ductility","authors":"Jingyi Hu, Tong Gao, Mengshuang Fu, Weikang Wu, Guiliang Liu, Jingyu Qin, Xiangfa Liu","doi":"10.1016/j.msea.2025.148777","DOIUrl":"10.1016/j.msea.2025.148777","url":null,"abstract":"<div><div>Novel (Al<sub>2</sub>O<sub>3</sub>+SiC + Al<sub>3</sub>BC)/Al composites were successfully synthesized via in-situ reactions within the Al-B<sub>2</sub>O<sub>3</sub>-SiC system, aiming to significantly enhance strength and stiffness while maintaining favorable ductility. The resulting composites exhibit a hybrid microstructure comprising uniformly dispersed in-situ γ-Al<sub>2</sub>O<sub>3</sub> nanoparticles and core-shell structured SiC@Al<sub>3</sub>BC particles, in which ex-situ SiC is coated by an in-situ formed Al<sub>3</sub>BC shell. Among the compositions studied, the Al-5B<sub>2</sub>O<sub>3</sub>-10SiC composite exhibited the most balanced combination of properties at room temperature, with a Young's modulus of 104 ± 1 GPa, an ultimate tensile strength (UTS) of 440 ± 4 MPa, and an elongation to failure (EL) of 4.1 ± 0.6 %. Notably, this composite also demonstrated significant thermal stability, retaining a UTS of 191 ± 6 MPa and an EL of 3.7 ± 0.3 % at 350 °C. The concurrent enhancement in stiffness and strength is attributed to synergistic reinforcement mechanisms, including the rule-of-mixtures contribution from high-modulus phases, nano-scale strengthening from Al<sub>2</sub>O<sub>3</sub>, and improved load transfer enabled by the SiC@Al<sub>3</sub>BC-Al interface. Further increases in SiC content to 20 wt% or the B<sub>2</sub>O<sub>3</sub> content to 10 wt% led to additional improvements, achieving moduli of 114 ± 2 GPa and 118 ± 2 GPa, and UTS values of 548 ± 6 MPa and 538 ± 3 MPa, respectively. These results demonstrate the potential of the proposed composite design for advanced applications operating under both ambient and elevated temperature conditions.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"943 ","pages":"Article 148777"},"PeriodicalIF":6.1,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572564","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}
Xiaoqian Xue , Qiuguang Zhang , Fugang Lu , Xinggen Guo , Yubin Li , Shengquan Xia , Qianrun Zhang , Haodong Li , Panpan Lin , Ce Wang , Tiesong Lin , Peng He
{"title":"Bonding of Al-Si and Ti-Ta dissimilar alloys via hot isostatic Pressing: Microstructure and interface stability","authors":"Xiaoqian Xue , Qiuguang Zhang , Fugang Lu , Xinggen Guo , Yubin Li , Shengquan Xia , Qianrun Zhang , Haodong Li , Panpan Lin , Ce Wang , Tiesong Lin , Peng He","doi":"10.1016/j.msea.2025.148782","DOIUrl":"10.1016/j.msea.2025.148782","url":null,"abstract":"<div><div>This study proposes a three-dimensional diffusion bonding (3D-DB) strategy for achieving metallurgical joining between Al-Si and Ti-Ta alloys with markedly dissimilar physical and mechanical properties. The technique is applicable to the fabrication of geometrically complex tubular components operating under extreme thermomechanical conditions, where conventional welding methods are often inadequate for ensuring structural and thermal reliability. The 3D-DB process employs gas-phase isotropic pressurization at 130 MPa to suppress unidirectional plastic deformation and promote uniform atomic diffusion at the bonding interface, resulting in the formation of a continuous nanoscale diffusion layer. Microstructural analysis reveals that the Al-Si region undergoes significant plastic deformation, primarily attributed to creep and grain boundary sliding, the Ti-Ta region exhibits a stress-induced β to α″ martensitic transformation. Thermal shock testing shows that the joints maintain consistent shear strength after multiple rapid thermal cycles, demonstrating reliable resistance to thermal cycling. These findings suggest that the 3D-DB technique offers a feasible solid-state bonding solution for dissimilar alloy systems and meets the performance requirements for the aerospace industry's demand for high-performance, thin-walled, and structurally intricate components.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"943 ","pages":"Article 148782"},"PeriodicalIF":6.1,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580534","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}
{"title":"Improving mechanical properties of an Al-Zn-Mg-Cu alloy during high stress creep aging via microalloying with Yb","authors":"Quanqing Zeng , Ya Li , Yu Liu , Lihua Zhan","doi":"10.1016/j.msea.2025.148767","DOIUrl":"10.1016/j.msea.2025.148767","url":null,"abstract":"<div><div>The performance of traditional Al-Zn-Mg-Cu alloys degrades rapidly under high stress, resulting in insufficient creep aging time and inadequate creep strain. A combination of electron and atomic microscopy characterization, along with first-principles calculations, was used to investigate the effect of Yb on the creep aging behavior and mechanical properties of Al-Zn-Mg-Cu alloys under high stress. The mechanism by which Yb extends the creep aging window was elucidated. First-principles calculations revealed that Yb tends to replace Al2 atoms in the η′ phase and Mg atoms in the η phase, raising the formation energies of η′ and η phases and inhibiting the coarsening of the precipitates. A trace addition of 0.3 wt% Yb induces a new primary phase of Al<sub>3</sub>(Yb, Zr), and further refine the grain size to 30.48 ± 2.3 μm. Under high-stress creep aging, the peak strength of 0.3 Yb alloy was achieved at 4 h, with a yield strength of 667.7 MPa. The yield strength of 0.3 Yb alloy remained stable, maintaining 628.2 MPa even after aging time of 8 h. The addition of Yb extended the high-stress peak aging time from 2 h to 4 h, prolonging the peak aging time. The 0.3 Yb alloy exhibited a \"2–8 h aging strengthening peak region,\" demonstrating better performance stability, reduced fluctuation, and a yield strength above 600 MPa. This contrasts with the Yb-free alloy, which only showed a transient peak aging region (2 h). The addition of Yb effectively increased the formation energies of the η′ and η phases, suppressed the coarsening of the η′ to η phase, and extended the process window for the synergy of creep strain and aging precipitation.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"943 ","pages":"Article 148767"},"PeriodicalIF":6.1,"publicationDate":"2025-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571277","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}
Huizhao Li , Bo Liu , Yiben Zhang , Xiaxu Huang , Jian Yang , Yi Wu , Ke Zhang , Yinglei Xue , Guochao Dong , Liren Wang
{"title":"Microstructural evolution, bonding mechanism, and fracture behavior of 6061-T4 Al/Q355B steel dissimilar joints fabricated by inertia friction welding","authors":"Huizhao Li , Bo Liu , Yiben Zhang , Xiaxu Huang , Jian Yang , Yi Wu , Ke Zhang , Yinglei Xue , Guochao Dong , Liren Wang","doi":"10.1016/j.msea.2025.148771","DOIUrl":"10.1016/j.msea.2025.148771","url":null,"abstract":"<div><div>This study explores the inertial friction welding (IFW) of 6061-T4 Al alloy with Q355B steel, with a focus on the evolution of the joint interface microstructure and its influence on mechanical properties. The bonding mechanism and fracture behavior are elucidated as well. The findings reveal the formation of an intermetallic compounds (IMCs) at the weld joint, including Al<sub>2</sub>Fe, Fe<sub>2</sub>Al<sub>5</sub>, Mg-rich Al<sub>2</sub>O<sub>3</sub>, and the Al matrix. Uneven distribution of heat, force, and friction states at the welding interface results in heterogeneous distributions of grain size, recrystallization degree, dislocations, and texture. The Brass {011} <211> texture shows a moderate Schmid factor and Taylor factor, whereas the P {011} <122> texture has a high Schmid factor and low Taylor factor. Grain refinement, dislocation motion inhibition, grain boundary strengthening, and the Brass {011} <211> texture enhance the joint performance. Conversely, the build-up of deformed grains, the presence of oxides, and the development of the P {011} <122> texture decrease the joint's ductility. The brittle IMC layers and Mg-rich Al<sub>2</sub>O<sub>3</sub> trigger crack initiation, serving as the primary fracture mechanism. The development of the P {011} <122> texture, coupled with sparse dislocations that initiate and propagate cracks, serves as the secondary fracture mechanism of the joint. The Schmid factor is linked to frictional heat, while the Taylor factor is associated with grain deformation and the formation of IMCs.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"943 ","pages":"Article 148771"},"PeriodicalIF":6.1,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580433","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}
Xu Yang , Zeming Wang , Yuxin Wang , Shiyu Niu , Qi Wen , Huijun Li , Ying Wang , Zhenwen Yang
{"title":"Unveiling the abnormal grain growth behavior in diffusion-bonded joints of zirconium alloys enhanced by gradient nanostructures","authors":"Xu Yang , Zeming Wang , Yuxin Wang , Shiyu Niu , Qi Wen , Huijun Li , Ying Wang , Zhenwen Yang","doi":"10.1016/j.msea.2025.148772","DOIUrl":"10.1016/j.msea.2025.148772","url":null,"abstract":"<div><div>Gradient nanostructured (GNS) materials have shown benefits in the diffusion bonding process; however, the occurrence of abnormal grain growth (AGG) of GNS materials at high temperatures remains insufficiently explored, particularly in relation to joint microstructure and properties. Herein, gradient nanostructures were fabricated on Zr-4 alloy plates via ultrasonic impact treatment, and subsequently utilized in diffusion bonding at 740–800 °C. The fabricated GNS-Zr exhibited a gradient microstructure, transitioning from surface nanograins (minimum of ∼40 nm) to coarse-grained regions within the matrix. During diffusion bonding, the thermal instability of GNS-Zr triggered AGG, forming a novel layered bimodal structure in the bonded joints, characterized by rapidly grown nanograins (RGGs), abnormal large grains (AGs), and normally grown grains (NGs). The AGs reached up to eight times the size of the original matrix grains at 800 °C, allowing their orientations to dominate the overall texture. The formation of AGs was driven by the non-uniform distribution of stored strain energy in GNS-Zr, with most grain orientations inherited from the original matrix. Although AGs exhibited lower hardness and greater susceptibility to twinning, the layered bimodal structure enhanced the joint shear strength through heterogeneous deformation between AGs and surrounding finer grains. This interaction provided additional work-hardening to the smaller grains while also improving the effective strength of AGs. Consequently, AGG contributed to a significant enhancement in joint shear strength by 39.8 % at 780 °C and 21.8 % at 800 °C compared to joints bonded with as-received Zr-4. These findings highlight the essential role of AGG in determining joint properties and offer insight into the microstructural design strategies for diffusion-bonded joints.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"943 ","pages":"Article 148772"},"PeriodicalIF":6.1,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580504","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}
Zhifei Yu , Shaojia Shi , Xingwen Zhang , Zesheng You , Yonghao Zhao
{"title":"Inverse Hall-Petch and nanocrystal-amorphous transition of broad-spectrum W content NiW alloys","authors":"Zhifei Yu , Shaojia Shi , Xingwen Zhang , Zesheng You , Yonghao Zhao","doi":"10.1016/j.msea.2025.148774","DOIUrl":"10.1016/j.msea.2025.148774","url":null,"abstract":"<div><div>Fabricating metallic materials with grain sizes below 10 nm, particularly in the range between 2.4 and 7.2 nm, poses a challenge. However, it is crucial to accurately identify Hall-Petch breakdown within this range. Moreover, there are differing opinions regarding the change in strength that occurs when nanocrystals transform into amorphous materials. This study involved the electroplating preparation of amorphous or nanometer NiW coatings spanning 1.9–15.8 nm by adjusting current density and temperature. The microstructure under tungsten atoms solid solution was characterized and measured surface hardness. The results revealed that the tungsten solid solution in FCC Ni alloy refines grain size and the strength follows the Hall-Patch relationship while the hardness of nanocrystal NiW alloy with 12.3 at% W regional maximum at 7.79 GPa at the critical point of 5.9 nm, significantly surpassing the 5.29 GPa hardness of pure nickel at 22.0 nm. After that, reverse Hall-Petch abnormal phenomenon begin. The annealed alloy of Ni-15.0 at% W had the similar trend and critical point at 5.0 nm. Following the transformation into an amorphous state, hardness further rises, reaching a pinnacle of 8.95 GPa of Ni-20.9 at%W. The values of solid solution hardening under various content of tungsten atoms were calculated. It suggests that the solid solution limitation of nanocrystal NiW which grain size bellowed 10.0 nm expanded. After removing the hardening by atoms solid solution, the similar Hall-Petch breakdown phenomenon was observed while the critical point was expansion offset to 8.6 nm which was approaching the critical point of nickel electrodeposited coating.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"943 ","pages":"Article 148774"},"PeriodicalIF":6.1,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144556974","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}
Zhengyan Zhang , Sencai Wang , Feng Chai , Xiaobing Luo , Shuo Ma , Zhongran Shi , Xiyang Chai , Zemin Wang
{"title":"Effect of the Ni content on the microstructure and mechanical properties of Cu-bearing high-strength steels","authors":"Zhengyan Zhang , Sencai Wang , Feng Chai , Xiaobing Luo , Shuo Ma , Zhongran Shi , Xiyang Chai , Zemin Wang","doi":"10.1016/j.msea.2025.148762","DOIUrl":"10.1016/j.msea.2025.148762","url":null,"abstract":"<div><div>Cu-bearing high-strength low-alloy (HSLA) steels are widely used in demanding applications requiring a balance of strength and low-temperature toughness, where Ni is a key alloying element influencing both microstructural evolution and mechanical properties. The effect of Ni content (1.5–3.5 wt%) on the strengthening mechanisms of Cu-bearing high-strength steels was systematically investigated. As Ni increased, the hardenability of the tested steels was significantly enhanced, and the microstructure gradually transformed into fully lath martensite from bainite/martensite mixed structure. Prior austenite grains as well as martensitic substructures were refined. Grain refinement strengthening was the dominant contributor to the increased yield strength. Higher Ni content also increased dislocation density and slightly raised the number density of Cu-rich nanoprecipitates, while having little effect on their average size (∼12 nm). Hall-Petch analysis combined with boundary misorientation evaluation identified the block as the effective strengthening unit, due to its high-angle boundaries that effectively impede dislocation motion.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"943 ","pages":"Article 148762"},"PeriodicalIF":6.1,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571276","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}