Intermetallics最新文献

{"title":"Undercooled liquid state properties and intermetallic compounds growth of ternary Fe-Tb-B alloy","authors":"Y. Ma ,&nbsp;Y.P. Zheng ,&nbsp;L. Hu ,&nbsp;S.H. Liu ,&nbsp;W. Zhai","doi":"10.1016/j.intermet.2025.108986","DOIUrl":"10.1016/j.intermet.2025.108986","url":null,"abstract":"<div><div>The substantial undercooling up to 217 K (0.15 times of the alloy liquidus temperature <em>T</em>_L) and rapid solidification of ternary Fe₇₀Tb₁₈B₁₂ alloy were achieved through electromagnetic levitation technique. The undercooled liquid surface tension, viscosity and diffusivity were measured versus temperature, from which the activation energies for viscous flow and atomic diffusion were deduced. As undercooling rose, the primary τ₁ (Tb₂Fe₁₄B) intermetallic compound transformed from faceted coarse dendrites to nonfaceted equiaxed grains, attributed to the reduced anisotropic growth velocity between low-index (004) and high-index (214) crystal planes. The dendrite growth velocity of primary τ₁ phase increased as a double-exponential function with its volume fraction up to 47 %. The peri-eutectic structures at small undercoolings showed a regular morphology featured by τ₂ (TbFe₄B₄) phase distributing in the interdendritic region of TbFe₂ phase, and their semi-coherent interface following orientation relationship of τ₂[101]//TbFe₂[011] and τ₂ <span><math><mrow><mo>(</mo><mrow><mn>11</mn><mover><mn>1</mn><mo>‾</mo></mover></mrow><mo>)</mo></mrow></math></span>//TbFe₂(100). If undercooling increased, the peri-eutectic τ₂ phase grew as small granules uniformly dispersing on TbFe₂ phase matrix while the interface relationship converted to τ₂[111]//TbFe₂[012] and τ₂ <span><math><mrow><mo>(</mo><mrow><mn>1</mn><mover><mn>1</mn><mo>‾</mo></mover><mover><mn>2</mn><mo>‾</mo></mover></mrow><mo>)</mo></mrow></math></span>//TbFe₂ <span><math><mrow><mo>(</mo><mrow><mn>12</mn><mover><mn>1</mn><mo>‾</mo></mover></mrow><mo>)</mo></mrow></math></span>. The corrosion current density of rapid solidification microstructures decreased by two orders of magnitude at the maximum undercooling, which was ascribed to the combination of increased volume fraction, the refinement effect of primary τ₁ intermetallic compound and the formation of irregular peri-eutectic (τ₂+TbFe₂) structures.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 108986"},"PeriodicalIF":4.8,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096572","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 phase stability and mechanical properties of Mg-Al-based lightweight complex concentrated alloys","authors":"Quan Dong ,&nbsp;Yufei Zhang ,&nbsp;Yuhao Chen ,&nbsp;Qian Shangguan ,&nbsp;Chengyu Peng ,&nbsp;Jing Zhang","doi":"10.1016/j.intermet.2025.109001","DOIUrl":"10.1016/j.intermet.2025.109001","url":null,"abstract":"<div><div>In this work, three Mg-rich lightweight complex concentrated alloys (LW-CCAs) with Al density classes, <em>i.e.</em>, Mg_77.5Al_12.5Li₅Zn_2.5Cu_2.5 (<em>at.</em>%), Mg₇₉Al_13.5Zn₃Cu₃Mn₁Ce_0.5 (<em>at</em>.%), and Mg₈₀Al₈Zn₇Gd_2.5Y_2.5 (<em>at.</em>%), have been designed according to the thermodynamic empirical guidelines and synthesized via a combination of mechanical alloying (MA) and cold-press sintering (CPS). The effects of composition and heat-treatment temperature on the microstructures and mechanical properties of LW-CCAs were analyzed. The results suggest that the microstructures of the as-milled Mg_77.5Al_12.5Li₅Zn_2.5Cu_2.5 and Mg₇₉Al_13.5Zn₃Cu₃Mn₁Ce_0.5 LW-CCAs predominantly consist of an HCP phase, while the as-milled Mg₈₀Al₈Zn₇Gd_2.5Y_2.5 LW-CCA exhibits only a single HCP structure. The LW-CCAs undergos distinct phase transformation with the precipitation of intermetallics after CPS. The Mg₈₀Al₈Zn₇Gd_2.5Y_2.5 LW-CCA has the highest phase stability as affected by the <em>T</em>_m, Δχ, Δ<em>H</em>_mix, and Δ<em>G</em>_mix parameters. Moreover, the as-milled LW-CCAs exhibit high hardness features owing to the combined result of fine grain effect, solid solution effect, and dislocation effect, among which the Mg₈₀Al₈Zn₇Gd_2.5Y_2.5 alloy possess the highest hardness of 1.53 GPa. The Mg₈₀Al₈Zn₇Gd_2.5Y_2.5 alloy sintered at 400°C exhibits excellent hardness and specific hardness, reaching 164.7 HV and 74.2 HV·cm³·g⁻¹, respectively.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 109001"},"PeriodicalIF":4.8,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096571","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 the anisotropic tensile properties of laser-directed energy deposition Ti-6Al-2.5Mo-1.5Cr-0.5Fe-0.3Si titanium alloy with subcritical isothermal annealing","authors":"Lanyun Qin ,&nbsp;Jiayu Gu ,&nbsp;Junzhen Yi ,&nbsp;Bo He ,&nbsp;Guang Yang ,&nbsp;Chao Wang","doi":"10.1016/j.intermet.2025.108977","DOIUrl":"10.1016/j.intermet.2025.108977","url":null,"abstract":"<div><div>The laser directed energy deposition (LDED) process is marked by a low nucleation rate and rapid solidification speed, which tends to form a coarse columnar prior β -grain structure. Heat treatment serves as a crucial method for altering the grain structure of high-strength titanium alloys and mitigating their mechanical property anisotropy. In this work, the influence of subcritical isothermal annealing on the grain structure and anisotropic tensile properties was investigated in Ti-6Al-2.5Mo-1.5Cr-0.5Fe-0.3Si titanium alloy fabricated by LDED. The results show that after subcritical isothermal annealing, the coarse prior columnar grains of the as-deposited samples are partially transformed into equiaxed grains. Its occurrence results from dislocation migration and subgrain boundary formation induced by subcritical isothermal annealing. Meanwhile, the anisotropy of mechanical properties has also been significantly improved. The tensile strength of the as-deposited specimens along the horizontal direction and the vertical direction were 1168.2 MPa and 1034.5 MPa respectively. After HT3 treatment, these values are 1043.1 MPa and 1043.2 MPa respectively, reducing the difference from 133.7 MPa to 0.1 MPa, improving the anisotropic tensile properties. This is caused by the sliding of α laths and the aggregation phenomenon of the α phase at the grain boundaries. Analyzing the sample's fracture surface reveals that its fracture mode has transformed from intergranular fracture before annealing to a mixed mode of intergranular and transgranular fracture after annealing. This study provides a foundation for eliminating anisotropy in heat treatment and advances the application of titanium alloy additive manufacturing in aerospace construction.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 108977"},"PeriodicalIF":4.8,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060906","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 influence of Mn and Cr elements on the isothermal oxidation behavior of γ-TiAl alloys","authors":"Deng Zehaochen ,&nbsp;Zhu Yue ,&nbsp;Tian Hao ,&nbsp;Zhang Guoqing ,&nbsp;Kang Yiyao ,&nbsp;Leng Xuesong ,&nbsp;Zhang Chao ,&nbsp;He Jianchao","doi":"10.1016/j.intermet.2025.108976","DOIUrl":"10.1016/j.intermet.2025.108976","url":null,"abstract":"<div><div>This study systematically analyzed the thermal exposure behavior of two gamma titanium aluminide alloys (Ti-48Al-2Mn-2Nb and Ti-48Al-2Cr-2Nb) to investigate the effects of Mn and Cr elements on the oxidation resistance of the alloys at different temperatures of 750 °C, 850 °C, and 950 °C. At 750 °C and short thermal exposure times, Mn increases the α₂ transformation temperature and reduces the α₂ phase content, thereby hindering the diffusion of oxidation atmosphere and enhancing the oxidation resistance of the alloy. At increasing temperature, Mn tends to form oxidation products, disrupting the continuity of the oxidation layer and reducing the bonding strength, which has a detrimental effect on the oxidation resistance of the alloy. At low Cr contents, as the thermal exposure time increases, Cr exists in the form of Cr³⁺, increasing the concentration of oxygen vacancies and promoting the growth of TiO₂, thereby weakening the oxidation resistance of the alloy. At 750 °C, Ti-48Al-2Mn-2Nb exhibits better oxidation resistance; at 850 °C, the two alloys have similar oxidation resistance; and at 950 °C, the oxidation scale thickness increases dramatically, with Ti-48Al-2Mn-2Nb experiencing severe oxidation layer shedding, whereas Ti-48Al-2Cr-2Nb shows relatively good oxidation resistance.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 108976"},"PeriodicalIF":4.8,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046572","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":"Interfacial intermetallic compounds formation at interface for joining selective laser melted and wrought Ti6Al4V alloy","authors":"Morteza Azarbarmas","doi":"10.1016/j.intermet.2025.109000","DOIUrl":"10.1016/j.intermet.2025.109000","url":null,"abstract":"<div><div>Taking advantage of both selective laser melted and wrought samples, joining them together is extremely interesting. In this study, specimens of selective laser melted and wrought Ti6Al4V alloy were diffusion bonded using Cu interlayer, as a first attempt, to evaluate the influence of bonding parameters on microstructural developments and the performance of joints. The diffusion bonding was accomplished using a simply designed fixture, with the industrial applicability, at 820, 850 and 870 °C, with a holding time of 2 h. Obtained joints were studied by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), X-ray diffractometry (XRD), micro-hardness measurement and shear strength test. The observation of microstructures showed that sound joints comprising several intermetallics can be formed by this method. The shear strength of about 125 MPa was obtained during bonding at 850 °C, in which diffusion layers comprising several intermetallic compounds - Ti₂Cu, TiCu, Ti₃Cu₄ and TiCu₂ - were detected inside the interface of joints.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 109000"},"PeriodicalIF":4.8,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046573","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":"Investigations on the effect of secondary treatments on Ti48Al2Cr2Nb alloy manufactured by electron beam powder bed fusion method","authors":"Guney Mert Bilgin ,&nbsp;Seren Ozer ,&nbsp;Kemal Davut ,&nbsp;Ziya Esen ,&nbsp;Arcan F. Dericioglu","doi":"10.1016/j.intermet.2025.108985","DOIUrl":"10.1016/j.intermet.2025.108985","url":null,"abstract":"<div><div>As-built Ti48Al2Cr2Nb alloy samples produced by electron beam powder bed fusion (PBF-EB) exhibited notable brittleness. The low ductility was attributed to coarse γ bands aligned perpendicular to the building and tensile direction. Additionally, variations in aluminum content and hardness between the coarse colonies and fine γ/α₂ lamellae contribute to this phenomenon. Electron backscattered diffraction (EBSD) studies revealed a higher amount of dislocation density and inherent strain after PBF-EB manufacturing. Hence, usage of Ti48Al2Cr2Nb alloy in the as-built condition in aviation applications with high loads and demanding environments is not found to be viable. To eliminate these negative aspects and make PBF-EB produced Ti48Al2Cr2Nb alloy available for demanding applications, two distinct post-processing heat treatments; namely, hot isostatic pressing (HIP) and annealing heat treatment (HT) were employed at 1200 °C. A comprehensive characterization covering microstructure analysis, EBSD, fracture surface examination, as well as room and high-temperature tensile tests allowed determination of the effect of post-processes. HIPing altered the banded structure observed in the as-built samples by increasing the amount of α₂ phase and grain size. On the other hand, HT made the banded structure more pronounced without significantly increasing the amount of α₂ phase. HT also strengthened the &lt;001&gt; texture, while HIPing introduced randomization of grains. On the other hand, complete recrystallization is achieved as a result of HT at 1200 °C for 2 h, whereas HIPing at the same temperature for 2 h induced only 80.5 % recrystallization. In both post-processes, dislocation density and inherent strain were reduced. Room temperature and high-temperature tensile tests demonstrated that both HIPing and HT eliminated the extreme brittleness of the as-built samples.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 108985"},"PeriodicalIF":4.8,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027591","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":"Dislocation mechanisms and mechanical behavior of highly concentrated Al-Mg (6.6 and 9.3 at.%) binary alloys","authors":"Jing Su ,&nbsp;Xiaoxiang Wu ,&nbsp;Huan Zhao ,&nbsp;Juan Li ,&nbsp;Zhiming Li ,&nbsp;Shae K. Kim ,&nbsp;Dirk Ponge","doi":"10.1016/j.intermet.2025.108981","DOIUrl":"10.1016/j.intermet.2025.108981","url":null,"abstract":"<div><div>Al-Mg alloys are promising structural materials due to their strong solid solution strengthening, high strain-hardening capacity, and good formability. To explore the strengthening potential of higher Mg concentrations, this study investigates a naturally aged Al-9.3 at.% Mg alloy exhibiting spinodal decomposition and compares it to a solid-solution Al-6.6 at.% Mg reference alloy. Atom probe tomography (APT) and high-resolution scanning transmission electron microscopy (STEM) reveal spinodal modulations in Al-9.3 Mg, with a dominant wavelength of 11.7 nm and a Mg fluctuation amplitude of ∼3.6 at.%. These modulations align along the &lt;100&gt; direction and generate periodic lattice distortions at the coherent, compositionally diffuse interfaces of Mg-rich and Mg-lean regions, arising from the significant atomic size mismatch (21 %) between Al and Mg atoms. Compared to AlMg6.6, the AlMg9.3 alloy exhibits significantly higher yield and ultimate tensile strengths, while maintaining similar ductility (∼32 %). Al-6.6 Mg exhibits frequent cross-slip on {111} planes, whereas Al-9.3 Mg displays wavy slip lines, and dislocation structures indicative of jogs, loops, and dipoles. The enhanced work hardening behavior observed in Al-9.3 Mg is attributed to the interactions between dislocations and spinodal structures, which hinder dislocation motion and promote dislocation accumulation. This study reveals the underlying dislocation mechanisms in spinodal modulated structures and the corresponding strengthening effects, shedding light on the development of lightweight and high-strength Al-Mg alloys with elevated Mg contents.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 108981"},"PeriodicalIF":4.8,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020280","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":"Effect of Ru addition on γ/γ′ partitioning behavior of alloying elements, γ/γ′ lattice misfit and 1200 °C creep properties of Ni-based single-crystal superalloy","authors":"Haodong Duan ,&nbsp;Geng Li ,&nbsp;Xiaoyu Chen ,&nbsp;Cheng Ai ,&nbsp;Jie Kang ,&nbsp;Yi Ru ,&nbsp;Heng Zhang ,&nbsp;Yanling Pei ,&nbsp;Shusuo Li ,&nbsp;Shengkai Gong ,&nbsp;Huibin Xu","doi":"10.1016/j.intermet.2025.108987","DOIUrl":"10.1016/j.intermet.2025.108987","url":null,"abstract":"<div><div>The influence of Ru addition on γ/γ′ partitioning behavior of alloying elements, solid solution strengthening degree of γ and γ′ phases, γ/γ′ lattice misfit and 1200 °C/80 MPa creep properties of Ni-based single-crystal superalloys was detailed investigated. Ru addition increased 1200 °C/80 MPa rupture life of Ni-based single-crystal superalloy from 125.93 ± 5.61 h to 179.87 ± 4.43 h. The experimental single-crystal superalloys exhibited a high γ′ phase volume fraction at 1200 °C, which contributed to the superior 1200 °C/80 MPa creep properties of both Ru-free and Ru-containing single-crystal superalloys. In this study, Ru addition increased Mo, Cr, and Re contents in γ phase, and thus increased both solid solution strengthening degree and lattice constant of γ phase. These effects collectively decreased γ/γ′ lattice misfit and γ/γ′ interfacial dislocation network spacing, which increased γ/γ′ interfacial strengthening effect, and ultimately increased 1200 °C/80 MPa creep life. Furthermore, it was revealed that the 1200 °C/80 MPa creep/stress rupture lives of single-crystal superalloys with low thermal stability of γ′ phase, creep/stress rupture lives are dominated by volume fraction of γ′ phase. In contrast, for single-crystal superalloys with high thermal stability of γ′ phase (such as the two single crystal superalloys in this study), the 1200 °C/80 MPa creep/stress rupture lives were primarily governed by γ/γ′ lattice misfit. Therefore, in order to design single-crystal superalloys with excellent 1200 °C/80 MPa creep performance, it is essential to simultaneously improve thermal stability of γ′ phase and decrease γ/γ′ lattice misfit of single crystal superalloys.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 108987"},"PeriodicalIF":4.8,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020278","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":"Thermokinetics driven microstructural evolution during laser-based additive manufacturing of γ-TiAl alloy","authors":"K.N. Chaithanya Kumar ,&nbsp;Madhavan Radhakrishnan ,&nbsp;Zane Weldon Hughes ,&nbsp;Selvamurugan Palaniappan ,&nbsp;Shashank Sharma ,&nbsp;Rajarshi Banerjee ,&nbsp;Satyam Suwas ,&nbsp;Narendra B. Dahotre","doi":"10.1016/j.intermet.2025.108984","DOIUrl":"10.1016/j.intermet.2025.108984","url":null,"abstract":"<div><div>This work investigates effects of thermokinetics on evolution of microstructure in additively manufactured Ti4822 alloy fabricated with identical processing parameters under intrinsically different thermokinetic conditions associated with heights of 4 mm and 10 mm with a same base cross-sectional area. Despite similar printing conditions, distinctly different microstructures were observed due the different thermokinetics experienced by each one of them. While 4 mm component possessed a fine scale lamellar γ+α₂ microstructure, the 10 mm component generated coarsened γ grains with spheroidized α₂ pockets. A component-scale thermal model was employed to explain the thermokinetics driven phase transformations. The difference in microstructure is attributed to thermal histories experienced during fabrication by components of different volumes. Specifically, rapid cooling from above the α-transus temperature promoted fine γ-lath formation in the 4 mm component, whereas slower cooling through the γ+α phase field in the 10 mm component resulted in coarsened γ grains. The nanoindentation based hardness and elastic modulus correlates well with the microstructural changes observed in the fabricated components. These findings offer valuable insights into tailoring microstructures by exploiting the novel thermokinetics intrinsic to additive manufacturing processes.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 108984"},"PeriodicalIF":4.8,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020279","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":"Tailoring concentrations of principal elements to promote Hall-Petch strengthening of NiCoCrFe high entropy alloys","authors":"Jun Chen ,&nbsp;Ziyang Zhang ,&nbsp;Zhongsheng Yang ,&nbsp;Xin Liu ,&nbsp;Ruixing Shi ,&nbsp;Feng He","doi":"10.1016/j.intermet.2025.108999","DOIUrl":"10.1016/j.intermet.2025.108999","url":null,"abstract":"<div><div>Hall-Petch strengthening in high-entropy alloys (HEAs) involves complex interactions between grain boundary segregation and unstable stacking fault energy (USFE), yet their competitive roles remain unresolved. Here, we design three non-equiatomic NiCoCrFe HEAs (Ni₄₀Co₂₀Cr₂₀Fe₂₀, Ni₂₀Co₄₀Cr₂₀Fe₂₀ and Ni₂₀Co₂₀Cr₂₀Fe₄₀) to decouple these effects through controlled elemental variations. Systematic experiments reveal that: (i) Friction stress scales linearly with lattice distortion degree, confirming solid-solution strengthening dominated by atomic size misfit; (ii) Hall-Petch coefficients exhibit an anomalous sequence: Co40 (426 MPa μm^0.5) &gt; Fe40 (360 MPa μm^0.5) &gt; Ni40 (320 MPa μm^0.5), defying predictions from singular grain boundary segregation or USFE theories; (iii) A unified competition mechanism framework is established, classifying systems into four types: non-segregation, segregation-transition, weak segregation, and strong segregation. Crucially, in weak-segregation systems, higher USFE overrides Cr segregation to maximize Hall-Petch coefficient. This work provides fundamental insights into the antagonistic grain boundary segregation-USFE interplay governing Hall-Petch behavior, enabling targeted optimization of strength-ductility trade-offs in HEAs.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 108999"},"PeriodicalIF":4.8,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145009892","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}