Materials Science and Engineering: A最新文献

{"title":"Enhancing the surface integrity and high-stress-concentration notched fatigue performance of 18CrNiMo7-6 carburized steel via ultrasonic surface rolling","authors":"LanRong Liu ,&nbsp;Lei Li ,&nbsp;HaoNan Kang ,&nbsp;GuangTao Xu ,&nbsp;YongTao Ma ,&nbsp;MingHao Zhao ,&nbsp;ZengTao Chen ,&nbsp;ZhiHua Liu","doi":"10.1016/j.msea.2025.149629","DOIUrl":"10.1016/j.msea.2025.149629","url":null,"abstract":"<div><div>This study investigates the effects of the ultrasonic surface rolling process (USRP) on the surface integrity and fatigue performance of 18CrNiMo7-6 alloy steel with a high stress concentration factor (<em>K</em>_t = 3). Systematic evaluations under static loads of 400 N and 800 N showed that USRP significantly enhances surface properties: it reduces roughness (<em>Ra</em>) to 0.25 μm and stress concentration coefficient (<em>K</em>_st) to 1.09, while eliminating grinding-induced surface defects. At 800 N, a gradient nanostructure (GNS) forms on the surface, with grain size refined to 0.34 μm at 20 μm depth; dislocation density and low-angle grain boundary proportion increase by 83.77 % and 175.46 %, respectively. An approximately 800 μm-thick gradient hardened layer is generated, exhibiting a maximum microhardness of 847 HV and residual compressive stress of −1440 MPa. Fatigue testing revealed the fatigue limit increases from 627.66 MPa to 1175 MPa (an 85.49 % enhancement), accompanied by a shift in crack initiation sites from surface grinding marks to subsurface oxide inclusions at 0.481 mm depth. This remarkable fatigue improvement is attributed to a multi-scale synergistic mechanism: (1) USRP-induced GNS enhances yield strength via the Hall-Petch effect and increases dislocation density, raising the crack initiation threshold, while improved surface quality further reduces crack nucleation probability; (2) introduced residual compressive stress effectively lowers the driving force for crack propagation, significantly retarding crack growth.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"952 ","pages":"Article 149629"},"PeriodicalIF":7.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145838837","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":"The effect of various grain sizes and secondary phase precipitation on the microstructure and mechanical properties of the rotary-swaged Al0.35CoCrFeNi complex concentrated alloy","authors":"Kateryna Ulybkina ,&nbsp;Kateryna Kamyshnykova ,&nbsp;Tatiana Pelachová ,&nbsp;Lisa Claeys ,&nbsp;Kim Verbeken ,&nbsp;Tom Depover ,&nbsp;Alena Klimová ,&nbsp;Zuzana Hájovská ,&nbsp;Ivan Petryshynets","doi":"10.1016/j.msea.2025.149691","DOIUrl":"10.1016/j.msea.2025.149691","url":null,"abstract":"<div><div>This study examines the impact of grain size and secondary strengthening phases on the mechanical properties of a cold-swaged Al_0.35CoCrFeNi complex concentrated alloy (CCA). For this purpose, rotary swaging at room temperature is applied to as-cast CCA, followed by recrystallization annealing at 1150 °C for 3, 20, 120, and 480 min to achieve a uniform microstructure with varying grain sizes. Afterward, the alloy undergoes precipitation annealing at 700 °C and 900 °C for 25 h to form secondary phases (L1₂, B2, σ-phase). Depending on the grain size and precipitation of secondary phases, the yield strength and ultimate tensile strength increase from 238 MPa to 663 MPa–657 MPa and 1020 MPa, respectively, while maintaining a ductility of approximately 37 %. The effect of grain size on the alloy's strength is evaluated using the Hall-Petch relationship. The calculated values of the hardening coefficients for the single-phase CCA are <em>k</em>_<em>h</em> = 277 HVμm^−1/2 and <em>k</em>_<em>σ</em> = 655 MPa μm^−1/2, which decrease with the precipitation of secondary strengthening phases. Additionally, a quantitative evaluation of the strengthening effect is conducted by calculating the different contributions to the overall strengthening of the studied CCA. It is demonstrated that the nanodispersed L1₂ phase provides the most significant contribution to improving mechanical properties, compared to the strengthening effects of grain boundaries and B2 phase particles.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"952 ","pages":"Article 149691"},"PeriodicalIF":7.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145838897","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":"Modulated precipitation of dispersoids and strength-ductility synergy via multi-step pre-treatments in an Al-Mg-Mn-Fe-Zr-Cr-Si alloy","authors":"Ziyan Hu ,&nbsp;Feng Qian ,&nbsp;Jinyue Li ,&nbsp;Chunan Li ,&nbsp;Zijian Wang ,&nbsp;Yang Li ,&nbsp;Chun Guo ,&nbsp;Shiwei Pan ,&nbsp;Xingwang Cheng","doi":"10.1016/j.msea.2026.149809","DOIUrl":"10.1016/j.msea.2026.149809","url":null,"abstract":"<div><div>Conventional 5xxx Al-Mg alloys are typically non-heat-treatable, with their strength limited by solid solution and work hardening. Dispersion strengthening is a potent strategy to overcome this limitation, but its effectiveness is often hindered by the sluggish and insufficient precipitation of thermally stable dispersoids. To promote dispersion kinetics, this work introduced a multi-step pre-treatment, integrating pre-aging (PA, 300 °C/8 h) and pre-straining (PS, 10 % cold rolling), in a novel Al-Mg-Mn-Fe-Zr-Cr-Si alloy. This PA + PS protocol constructed a unique composite microstructure, featuring Mn-rich solute clusters, β-Mg₂Si nanoparticles and a high density of dislocations. Upon subsequent aging at 400 °C, the dislocation networks strongly interacted with β-Mg₂Si to cooperatively facilitate the heterogeneous nucleation of Mn-rich dispersoids, while the residual Mn-rich solute clusters in Al-matrix progressively transformed into dispersoids. This dual precipitation pathway effectively accelerated the aging kinetics and enhanced the spatial uniformity of dispersoids, thus drastically minimizing dispersoid-free zones (DFZs). Consequently, samples subjected to PA + PS exhibited a superior strength-ductility synergy after aging at 400 °C for 12 h, with yield strength, ultimate strength and elongation increased by 34 %, 40 % and 23 % over the as-cast counterpart. Furthermore, it demonstrated exceptional thermal stability, with negligible loss of strength even after prolonged 400 °C aging until 200 h, overwhelming the PS pre-treated and as-cast samples. This work establishes a transformative dispersion-strengthening paradigm mediated by the synergy of pre-aging and pre-straining, providing foundational insights for developing advanced, thermally stable 5xxx alloys with high strength-ductility synergy.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"953 ","pages":"Article 149809"},"PeriodicalIF":7.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023557","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":"Temperature-dependent deformation mechanisms and strengthening behavior of a novel Ni-based superalloy with bimodal γ′ precipitate distribution","authors":"Xinyu Meng ,&nbsp;Chao Tang ,&nbsp;Shaomin Lyu ,&nbsp;Xingfei Xie ,&nbsp;Jian Jia ,&nbsp;Jinglong Qu","doi":"10.1016/j.msea.2026.149784","DOIUrl":"10.1016/j.msea.2026.149784","url":null,"abstract":"<div><div>High-temperature tensile performance is a critical indicator of the mechanical reliability of Ni-based superalloys. In this study, a newly designed Ni-based superalloy was systematically investigated from room temperature to 900 °C to elucidate the coupling between microstructural characteristics, mechanical response, and deformation mechanisms. Fine-grained (10.7 μm) and coarse-grained (97 μm) microstructures were obtained through multi-stage heat treatments. The FG alloy exhibits superior yield and tensile strength below 750 °C, reaching 1340 MPa and 1740 MPa at room temperature and retaining 1208 MPa and 1267 MPa at 750 °C, which is primarily attributed to its higher grain boundary density and enhanced grain-boundary-mediated strengthening. However, the FG alloy shows a pronounced ductility drop at 815 °C, with the elongation decreasing to 9 %. In contrast, the CG alloy demonstrates enhanced strength retention at elevated temperatures, maintaining an ultimate tensile strength and yield strength of 801 MPa and 770 MPa at 900 °C, corresponding to a tensile strength retention of 54 % (compared with 38 % for the FG alloy), together with a stable elongation of 8.5 %. This superior high-temperature stability is associated with a lower grain boundary density and a higher fraction of Σ3 special boundaries (42.6–55.9 %). Microstructural analysis reveals a bimodal γ′ precipitate distribution in both microstructures, with fine secondary γ′ precipitates (FG: 82 nm, 48 %; CG: 92 nm, 57 %) dominating strengthening through short-range dislocation–precipitate interactions, and coarse primary γ′ precipitates (FG: 1.54 μm, 7.6 %; CG: 3.19 μm, 0.5 %) facilitating deformation accommodation by pinning grain boundary migration, thereby enabling a synergistic balance between strength and ductility over a wide temperature range. Transmission electron microscopy and critical resolved shear stress analysis demonstrate a temperature-dependent transition in deformation mechanisms from γ′ shearing to Orowan looping in the range of 815–900 °C. In addition, Co/Ti solute segregation at twin interfaces reduces interfacial energy and suppresses defect migration, further stabilizing the γ/γ′ microstructure and enhancing high-temperature strength. These findings provide mechanistic insight for the microstructural design of advanced Ni-based superalloys.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"953 ","pages":"Article 149784"},"PeriodicalIF":7.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023554","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":"Mechanistic insight into suppression of size effect in pure titanium foils fabricated via asymmetric rolling","authors":"Baohong Guo ,&nbsp;Haitao Gao ,&nbsp;Zhide Li ,&nbsp;Denis Pustovoytov ,&nbsp;Alexander Pesin ,&nbsp;Charlie Kong ,&nbsp;Hailiang Yu","doi":"10.1016/j.msea.2025.149692","DOIUrl":"10.1016/j.msea.2025.149692","url":null,"abstract":"<div><div>The mechanical strength of pure titanium foils generally tends to decrease once the size effect comes into play. This work is dedicated to suppressing the size effect and elucidating the underlying mechanism. The microstructure and mechanical properties of pure titanium foils (grade 4) were systematically investigated. The size effect was effectively postponed from the 300 μm–200 μm range down to 200 μm–100 μm range by employing the asymmetric rolling. The grain refinement and dislocation density were significantly enhanced due to the macro shear bands and non-prismatic slip. The island-type dislocation pile-ups and cell-like structures were formed in the asymmetrically rolled foils. These microstructural features impeded the movement of dislocations, thereby providing additional hardening that effectively suppressed the size effect. The yield strength along the rolling direction increased to 895 MPa and 934 MPa when the foil thickness was reduced to 300 μm (symmetric rolling) and 200 μm (asymmetric rolling), respectively.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"953 ","pages":"Article 149692"},"PeriodicalIF":7.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847544","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":"Assessing machine learning predictions of austenitic steel compositions for optimum mechanical response","authors":"Linh Thi Hoai Nguyen ,&nbsp;Kaveh Edalati ,&nbsp;Vijayvargia Kshitij ,&nbsp;Mohsen Dadfarnia ,&nbsp;Aleksandar Staykov ,&nbsp;Toshihiro Tsuchiyama ,&nbsp;Masanobu Kubota ,&nbsp;Hisao Matsunaga ,&nbsp;Jessica Anne Krogstad ,&nbsp;Petros Sofronis","doi":"10.1016/j.msea.2025.149714","DOIUrl":"10.1016/j.msea.2025.149714","url":null,"abstract":"<div><div>Understanding and predicting mechanical properties such as proof stress (yield strength), ultimate tensile strength, elongation to failure, and reduction in area are essential for screening the application of austenitic stainless steels in adverse chemomechanical environments. However, experimental determination of these properties is time-consuming, labor-intensive, and costly—especially under extreme conditions, which requires advanced experimental capabilities. In this study, we leverage a large-scale, curated dataset comprising 2180 experimental entries of austenitic alloys to develop machine learning (ML) models capable of predicting these key mechanical properties as <em>functions of composition, solution treatment condition, and testing temperature</em>. We systematically evaluate a range of ML algorithms, namely linear regression, kernel ridge regression, extreme gradient boosting, and artificial neural network. Among these, the extreme gradient boosting achieves the highest predictive accuracy, with <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> scores of 0.946 and 0.985 for proof stress and ultimate tensile strength, respectively. To further enhance model performance, we explore ensemble learning and transfer learning strategies. The transfer learning approach that leverages interdependencies between mechanical properties reduces the mean percentage error by 21.0% and increases <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> score by 3.1% in predicting reduction in area, compared to the original artificial neural network model. Our results show that ML models trained on well-structured experimental data can serve as an efficient and reliable tool for exploring the effect of composition on screening metrics. This work highlights the potential of data-driven approaches to accelerate the design and optimization of high-performance austenitic alloys. Furthermore, obtaining feature importance and insights from extreme gradient boosting using Shapley Additive Explanation tool provides valuable understanding of how features contribute to the prediction of mechanical properties.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"953 ","pages":"Article 149714"},"PeriodicalIF":7.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145882850","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":"Validation of the sensitivity and accuracy of ultrasonic inspection of HGN200 superalloy: Detection of all detrimental microscopic inclusions and their effects on fatigue properties","authors":"Hideaki Nishikawa ,&nbsp;Yoshiyuki Furuya ,&nbsp;Toshio Osada ,&nbsp;Satoshi Utada ,&nbsp;Ayako Ikeda ,&nbsp;Motoki Okuno ,&nbsp;Daisuke Nagahama","doi":"10.1016/j.msea.2025.149682","DOIUrl":"10.1016/j.msea.2025.149682","url":null,"abstract":"<div><div>To establish a strategy for managing microscopic inclusions in Ni–Co-based powder metallurgy HGN200 superalloys, this study examined the accuracy and sensitivity of ultrasonic testing (UT) by revealing certain detected inclusions that acted as fatigue-fracture origins. Several of these detectable inclusions were also shown to not affect the fatigue properties. First, high-frequency UT was conducted to identify the locations and sizes of inclusions. Next, ultrasonic fatigue testing was performed using fatigue specimens that were precisely machined to contain one of the inclusions previously detected by UT to confirm the actual inclusion size and its effect on the fatigue properties. The results showed that the location and size of inclusions—including those under 100 μm in diameter—could be successfully identified using UT. The difference between UT-measured inclusion diameters and the diameters of those which appeared on fatigue-fracture surfaces was within 50 μm. It was also evident that inclusion sizes below 100 μm as identified by UT did not appear on the fatigue-fracture surface; instead, microstructural facets were observed. In brief, inclusion sizes below 100 μm as identified by UT did not have any negative effects on the fatigue properties of HGN200 and could be regarded as harmless inclusions. Consequently, the use of UT in advance can reveal the sizes and locations of harmful inclusions. Cross-sectional observations of the fatigue-fracture origins show microstructural facets that correspond to isolated large grains, related to the concentration of Fe.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"953 ","pages":"Article 149682"},"PeriodicalIF":7.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145882919","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":"Effects of Al-5Ti-1B-xCe refiners on microstructure and tensile properties of Al-5.0Mg-3.0Zn-1.0Cu alloy at different cooling rates","authors":"Shenshen Cui ,&nbsp;Qiang Lu ,&nbsp;Dezhi Li ,&nbsp;Haiyan Jiang ,&nbsp;Qudong Wang ,&nbsp;Huisheng Cai","doi":"10.1016/j.msea.2026.149820","DOIUrl":"10.1016/j.msea.2026.149820","url":null,"abstract":"<div><div>In this investigation, the effects of Al-5Ti-1B-xCe (x = 0, 4, 8, 12 wt%) refiners on the grain size, microstructure, and mechanical properties of the Al-5.0Mg-3.0Zn-1.0Cu alloy under different cooling rates were investigated. The results showed that, within the cooling rate range of 9.5–33.6 °C/s, the Al-5Ti-1B-xCe (x = 4, 8, 12) refiners exhibit superior refinement effects on the secondary dendrite arm spacing (SDAS), the width of the Mg₃₂(AlCuZn)₄₉ phase, and the size of the Al₃Fe phase in the Al-5.0Mg-3.0Zn-1.0Cu alloy compared with the Al-5Ti-1B refiner, and the Al-5Ti-1B-4Ce refiner exhibits the strongest grain-refining effect. Moreover, as the cooling rate increases, the grain size, SDAS, the width of the Mg₃₂(AlCuZn)₄₉ phase, and the size of the Al₃Fe phase are refined, while in the aged condition, the precipitation-free zone (PFZ) width and the size of precipitates is reduced. Compared with the alloy refined by the Al-5Ti-1B refiner, the alloys refined by Al-5Ti-1B-xCe (x = 4, 8, 12) exhibit a reduced sensitivity of grain size to cooling rate; therefore, as the cooling rate increases, the extent of grain size reduction in the alloys refined by Al-5Ti-1B-xCe (x = 4, 8, 12) becomes smaller. The precipitate diameter shows a unimodal distribution when the alloy is refined by the Al-5Ti-1B refiner, while a bimodal distribution is observed after refinement by the Al-5Ti-1B-xCe (x = 4, 12) refiners. Compared with the alloy refined by the Al-5Ti-1B refiner, the aged Al-5.0Mg-3.0Zn-1.0Cu alloy refined by the Al-5Ti-1B-4Ce and Al-5Ti-1B-8Ce refiners exhibit higher strength and elongation. For alloys refined by the same refiner, the strength and elongation of the aged Al-5.0Mg-3.0Zn-1.0Cu alloy increase with increasing cooling rate.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"954 ","pages":"Article 149820"},"PeriodicalIF":7.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037420","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":"Engineered ωiso phase enable deformation-induced mechanisms strength and plasticity synergy in a novel Ti-531 metastable β titanium alloy","authors":"Irfan Ali Abro ,&nbsp;Lin Yang ,&nbsp;Qunbo Fan ,&nbsp;Kamal Mustafa","doi":"10.1016/j.msea.2026.149806","DOIUrl":"10.1016/j.msea.2026.149806","url":null,"abstract":"<div><div>Metastable β-Ti alloys are known for their high strain hardening rates and excellent plasticity through the combined effects of transformation induced plasticity (TRIP) and twinning induced plasticity (TWIP) effects, yet their relatively low yield strength restrict structural applications. Improving yield strength without sacrificing ductility is thus a key challenge in these alloys. To address this long-standing strength-plasticity dilemma, we designed a novel metastable β-Ti alloy, Ti-5Mo-3Cr-1Zr (Ti-531), guided by d-electron theory, average electron-to-atom ratio <span><math><mrow><mo>(</mo><mover><mrow><mi>e</mi><mo>/</mo><mi>a</mi></mrow><mo>‾</mo></mover><mo>)</mo></mrow></math></span> and atomic radius difference <span><math><mrow><mo>(</mo><mover><mrow><mo>Δ</mo><mi>r</mi></mrow><mo>‾</mo></mover><mo>)</mo></mrow></math></span> criteria. By engineering nanoscale <span><math><mrow><msub><mi>ω</mi><mtext>iso</mtext></msub></mrow></math></span> phase precipitations, a strategy is demonstrated to concurrently strengthen the yield response and preserve high ductility in the Ti-531 alloy. The results show that these <span><math><mrow><msub><mi>ω</mi><mtext>iso</mtext></msub></mrow></math></span> particles substantially strengthen the alloy and activate a synergistic deformation-induced strengthening mechanism. This mechanism involves a sandwich-type composite twin/stress-induced <span><math><mrow><mi>ω</mi></mrow></math></span> <span><math><mrow><mo>(</mo><msub><mtext>SI</mtext><mi>ω</mi></msub><mo>)</mo></mrow></math></span> structures, interactions between twin/SIM (α”), and development of dislocation channels largely devoid of <span><math><mrow><msub><mi>ω</mi><mtext>iso</mtext></msub></mrow></math></span> phase synergistically accommodate localized strain. These dislocation channels facilitate to accelerate dislocation accumulation, promote forest hardening and suppress the impeding effect of <span><math><mrow><msub><mi>ω</mi><mtext>iso</mtext></msub></mrow></math></span> phase. As a result, the alloy aged at 423 K (A423) outperforms the hot-rolled solution-treated alloy (R1123) in yield strength (∼642 MPa, ∼28 % higher) with merely a slight (∼1.1 %) reduction in elongation, thus combining high strength with largely preserved ductility. This work introduces instability-control paradigm that harmonizes twin/ <span><math><mrow><msub><mtext>SI</mtext><mi>ω</mi></msub></mrow></math></span>/SIM-assisted deformation and dislocation channels strengthening to engineer high performance metastable β-Ti alloys.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"954 ","pages":"Article 149806"},"PeriodicalIF":7.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146006806","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":"Enhanced strength-ductility synergy in heterostructured metastable FeCoNiCrMo medium-entropy alloys","authors":"Jun Seok Lee ,&nbsp;Pil Wook Shin ,&nbsp;Peyman Asghari-Rad ,&nbsp;Auezhan Amanov ,&nbsp;Hyoung Seop Kim ,&nbsp;Jae Wung Bae","doi":"10.1016/j.msea.2025.149647","DOIUrl":"10.1016/j.msea.2025.149647","url":null,"abstract":"<div><div>In this study, ultrasonic nanocrystalline surface modification was applied to Fe₅₅Co₁₉Ni_8.5Cr_12.5Mo₅ (Co₁₉Ni_8.5) and Fe₅₅Co₂₀Ni₅Cr_12.5Mo_7.5 (Co₂₀Ni₅) medium-entropy alloys, resulting in a heterogeneous microstructure that enhanced the room-temperature yield strength by up to 82 % compared to the annealed condition with the aid of hetero-deformation-induced (HDI) strengthening. In particular, the lower FCC stability of the Co₂₀Ni₅ alloy relative to the Co₁₉Ni_8.5 alloy triggered a transition in the deformation mechanism—from twinning to deformation-induced phase transformation—thereby enhancing the HDI strengthening effect and further improving the strength-ductility synergy.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"952 ","pages":"Article 149647"},"PeriodicalIF":7.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145838727","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}