Pub Date : 2025-11-12DOI: 10.1016/j.intermet.2025.109078
Xuyang Wang , Yajun Zhou , Bo Ren , Jianxiu Liu , Aiyun Jiang
The high-temperature oxidation behavior of TiB2@Ti/AlCoCrFeNi2.1 eutectic high-entropy alloy matrix composites (EHEAMCs) sintered at 950°C, 1000°C, and 1050°C was systematically investigated under isothermal oxidation at 900°C in air. The oxidation kinetics of all EHEAMCs followed a two-stage parabolic law: an initial rapid oxidation phase (1–10 h) followed by a slower steady-state phase (10–100 h). After 100 h of oxidation, the EHEAMCs sintered at 950°C exhibited the highest mass gain of 0.85 mg/cm2, while the 1050°C-sintered sample demonstrated the lowest weight gain of 0.37 mg/cm2. The parabolic rate constant (Kp) decreased significantly with increasing sintering temperature, reaching a minimum value of 7.88 × 10−8mg2⋅cm−4⋅s−1 for the 1050°C EHEAMCs, indicating enhanced oxidation resistance. Cross-sectional analysis revealed distinct oxide layer configurations: 950°C and 1000°C EHEAMCs formed stratified structures with an outer TiO2-rich layer and an inner Al2O3-dominated layer, whereas the 1050°C EHEAMCs exhibited discontinuous surface Al2O3 with internal oxide precipitates. Oxidation mechanisms transitioned from cation-dominated outward diffusion to oxygen anion inward penetration, modulated by sintering-induced densification and interfacial bonding.
{"title":"Effect of sintering temperature on the high-temperature oxidation behavior of TiB2@Ti/AlCoCrFeNi2.1 eutectic high-entropy alloy matrix composites","authors":"Xuyang Wang , Yajun Zhou , Bo Ren , Jianxiu Liu , Aiyun Jiang","doi":"10.1016/j.intermet.2025.109078","DOIUrl":"10.1016/j.intermet.2025.109078","url":null,"abstract":"<div><div>The high-temperature oxidation behavior of TiB<sub>2</sub>@Ti/AlCoCrFeNi<sub>2.1</sub> eutectic high-entropy alloy matrix composites (EHEAMCs) sintered at 950°C, 1000°C, and 1050°C was systematically investigated under isothermal oxidation at 900°C in air. The oxidation kinetics of all EHEAMCs followed a two-stage parabolic law: an initial rapid oxidation phase (1–10 h) followed by a slower steady-state phase (10–100 h). After 100 h of oxidation, the EHEAMCs sintered at 950°C exhibited the highest mass gain of 0.85 mg/cm<sup>2</sup>, while the 1050°C-sintered sample demonstrated the lowest weight gain of 0.37 mg/cm<sup>2</sup>. The parabolic rate constant (<em>Kp</em>) decreased significantly with increasing sintering temperature, reaching a minimum value of 7.88 × 10<sup>−8</sup>mg<sup>2</sup>⋅cm<sup>−4</sup>⋅s<sup>−1</sup> for the 1050°C EHEAMCs, indicating enhanced oxidation resistance. Cross-sectional analysis revealed distinct oxide layer configurations: 950°C and 1000°C EHEAMCs formed stratified structures with an outer TiO<sub>2</sub>-rich layer and an inner Al<sub>2</sub>O<sub>3</sub>-dominated layer, whereas the 1050°C EHEAMCs exhibited discontinuous surface Al<sub>2</sub>O<sub>3</sub> with internal oxide precipitates. Oxidation mechanisms transitioned from cation-dominated outward diffusion to oxygen anion inward penetration, modulated by sintering-induced densification and interfacial bonding.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"188 ","pages":"Article 109078"},"PeriodicalIF":4.8,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526212","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 : 2025-11-10DOI: 10.1016/j.intermet.2025.109070
Meiyan Li , Jiayang Song , Pu Li , Lixin Song , Dan Li , Chunyang Hu , Bin Han
AlxCoCrFeNiTi0.25 (x = 0, 0.5, 0.6, 0.8, 1.0) coatings were fabricated via laser cladding and subsequently subjected to ion nitriding treatment to enhance their mechanical properties. Effect of ion nitriding on microstructures, phase composition, hardness and wear resistance of AlxCoCrFeNiTi0.25 cladding coatings were investigated by means of scanning electron microscopy(SEM), X-ray diffraction (XRD), Vickers microhardness testing and material surface performance comprehensive tester. The results revealed that the thickness of the nitriding layer initially increased and then decreased with increasing Al content. XRD analysis revealed that CoCrFeNiTi0.25 nitrided layer was composed of Fe4N and CrN while AlN appeared in the Al-containing AlxCoCrFeNiTi0.25 HEA coatings. The microhardness of the as-clad AlxCoCrFeNiTi0.25 coating gradually increased from 210HV0.2 to 610HV0.2 with an increase in Al content. After ion nitriding the microhardness of AlxCoCrFeNiTi0.25 nitrided layer further enhanced significantly, reaching 963.2HV0.2, 1035.3HV0.2,1065.5HV0.2, 1206HV0.2, 1276.3HV0.2, respectively when x value varied from 0 to 1.0. Moreover, compared with untreated laser cladding coatings, the wear resistance of the nitrided layers was improved while the Al1.0CoCrFeNiTi0.25 nitrided coating exhibited the lowest wear rate of 0.351 × 10−5cm3/(N/m), significantly lower than that of the corresponding cladding coating (2.66 × 10−5cm3/(N/m)). After nitriding treatment, the worn mechnism transformed into fatigue spallling and oxidative wear. In summary, ion nitriding effectively modified the microstructure and phase composition of AlxCoCrFeNiTi0.25 coatings, resulting in substantial improvements in hardness and wear resistance.
{"title":"Effect of ion nitriding on microstructures and properties of laser cladding AlxCoCrFeNiTi0.25 high entropy alloys coatings","authors":"Meiyan Li , Jiayang Song , Pu Li , Lixin Song , Dan Li , Chunyang Hu , Bin Han","doi":"10.1016/j.intermet.2025.109070","DOIUrl":"10.1016/j.intermet.2025.109070","url":null,"abstract":"<div><div>Al<sub>x</sub>CoCrFeNiTi<sub>0.25</sub> (x = 0, 0.5, 0.6, 0.8, 1.0) coatings were fabricated via laser cladding and subsequently subjected to ion nitriding treatment to enhance their mechanical properties. Effect of ion nitriding on microstructures, phase composition, hardness and wear resistance of Al<sub>x</sub>CoCrFeNiTi<sub>0.25</sub> cladding coatings were investigated by means of scanning electron microscopy(SEM), X-ray diffraction (XRD), Vickers microhardness testing and material surface performance comprehensive tester. The results revealed that the thickness of the nitriding layer initially increased and then decreased with increasing Al content. XRD analysis revealed that CoCrFeNiTi<sub>0.25</sub> nitrided layer was composed of Fe<sub>4</sub>N and CrN while AlN appeared in the Al-containing Al<sub>x</sub>CoCrFeNiTi<sub>0.25</sub> HEA coatings. The microhardness of the as-clad Al<sub>x</sub>CoCrFeNiTi<sub>0.25</sub> coating gradually increased from 210HV<sub>0.2</sub> to 610HV<sub>0.2</sub> with an increase in Al content. After ion nitriding the microhardness of Al<sub>x</sub>CoCrFeNiTi<sub>0.25</sub> nitrided layer further enhanced significantly, reaching 963.2HV<sub>0.2</sub>, 1035.3HV<sub>0.2</sub>,1065.5HV<sub>0.2</sub>, 1206HV<sub>0.2</sub>, 1276.3HV<sub>0.2</sub>, respectively when x value varied from 0 to 1.0. Moreover, compared with untreated laser cladding coatings, the wear resistance of the nitrided layers was improved while the Al<sub>1.0</sub>CoCrFeNiTi<sub>0.25</sub> nitrided coating exhibited the lowest wear rate of 0.351 × 10<sup>−5</sup>cm<sup>3</sup>/(N/m), significantly lower than that of the corresponding cladding coating (2.66 × 10<sup>−5</sup>cm<sup>3</sup>/(N/m)). After nitriding treatment, the worn mechnism transformed into fatigue spallling and oxidative wear. In summary, ion nitriding effectively modified the microstructure and phase composition of Al<sub>x</sub>CoCrFeNiTi<sub>0.25</sub> coatings, resulting in substantial improvements in hardness and wear resistance.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"188 ","pages":"Article 109070"},"PeriodicalIF":4.8,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526218","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 : 2025-11-10DOI: 10.1016/j.intermet.2025.109063
Yujun Wang , Yuping Wu , Zheng Wei , Junpeng Lv , Sheng Hong , Jiangbo Cheng , Shuaishuai Zhu
A Cu-based amorphous coating (C1) was fabricated via cold spraying and then annealed to yield samples with crystallinities of approximately 30 % (C2) and 60 % (C3). The phase evolution and corresponding nanomechanical characteristics were investigated, and a new method for identifying pop-in events was developed. C1 was found to have an amorphous structure with minor amounts of nano-ZrO2 and nano-TiO2. The crystallization products consisted of a primary phase Cu51Ti14 and a secondary phase CuTi. The hardness and elastic modulus of C1 were 6.50 ± 1.12 GPa and 99.55 ± 10.30 GPa, respectively. After annealing, the hardness exhibited a parabolic variation, whereas the elastic modulus increased linearly. The creep of C1 and C2 was governed by the activation of interstitial defects and free volume, whereas creep in C3 was mainly influenced by crystalline defects. The first-order differences of the loading curves for all three coatings followed a negative power-law distribution. Using the upper bound of the fitted 95 % prediction interval as a threshold provided a reliable criterion for identifying pop-in events. Pop-in events were prominent in both C1 and C3, whereas they were significantly suppressed in C2. This study advances the development of Cu-based amorphous alloys and proposes a feasible approach for the rapid and effective identification of pop-in events.
{"title":"Phase evolution and nanomechanical characteristics of cold-sprayed Cu-based amorphous coatings","authors":"Yujun Wang , Yuping Wu , Zheng Wei , Junpeng Lv , Sheng Hong , Jiangbo Cheng , Shuaishuai Zhu","doi":"10.1016/j.intermet.2025.109063","DOIUrl":"10.1016/j.intermet.2025.109063","url":null,"abstract":"<div><div>A Cu-based amorphous coating (C1) was fabricated via cold spraying and then annealed to yield samples with crystallinities of approximately 30 % (C2) and 60 % (C3). The phase evolution and corresponding nanomechanical characteristics were investigated, and a new method for identifying pop-in events was developed. C1 was found to have an amorphous structure with minor amounts of nano-ZrO<sub>2</sub> and nano-TiO<sub>2</sub>. The crystallization products consisted of a primary phase Cu<sub>51</sub>Ti<sub>14</sub> and a secondary phase CuTi. The hardness and elastic modulus of C1 were 6.50 ± 1.12 GPa and 99.55 ± 10.30 GPa, respectively. After annealing, the hardness exhibited a parabolic variation, whereas the elastic modulus increased linearly. The creep of C1 and C2 was governed by the activation of interstitial defects and free volume, whereas creep in C3 was mainly influenced by crystalline defects. The first-order differences of the loading curves for all three coatings followed a negative power-law distribution. Using the upper bound of the fitted 95 % prediction interval as a threshold provided a reliable criterion for identifying pop-in events. Pop-in events were prominent in both C1 and C3, whereas they were significantly suppressed in C2. This study advances the development of Cu-based amorphous alloys and proposes a feasible approach for the rapid and effective identification of pop-in events.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"188 ","pages":"Article 109063"},"PeriodicalIF":4.8,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526216","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 : 2025-11-08DOI: 10.1016/j.intermet.2025.109074
Jiatao Lv , Jiahao Liu , Shuwen Guo , Jing Zhang , Chunyu Chen , Chuanbo Zheng , Zhanfang Wu , Xiangyang Li , Dianchun Ju
CrMnFeCoNi high-entropy alloy (HEA) was fabricated via hot isostatic pressing (HIP), and its high-temperature corrosion behavior and mechanism in NaCl-KCl molten salts were systematically investigated. The alloy exhibited a single FCC phase with a homogeneous elemental distribution and no noticeable segregation. The corrosion products were mainly identified as Cr2O3, Mn2O3, Fe2O3, Mn3O4, and MnCr2O4 spinel oxides. At 650 °C and 750 °C, the alloy showed relatively stable surface morphologies, with both weight loss and corrosion rate increasing linearly with time. In contrast, at 850 °C, the surface morphology became more complex, dominated by porous spinel oxides, accompanied by a pronounced acceleration in weight loss and corrosion rate. By performing an Arrhenius fit of the linear rate constant kl at multiple temperatures, the activation energy of the linear corrosion process was determined to be 120.4 kJ/mol. Thermodynamic calculations of Gibbs free energy (ΔG) revealed that Mn and Cr possess high reactivity toward O2 and Cl2, leading to the preferential formation of Cr2O3-, Mn2O3-, and minor Fe2O3-rich oxide layers during the early corrosion stage. With prolonged exposure, progressive spallation of the oxide scale facilitated the ingress of molten salts, promoting severe substrate attack, the development of new Cr2O3- and Mn2O3-rich layers, internal oxidation, and the formation of increasingly coarse spinel oxides at the alloy surface.
{"title":"The corrosion behavior and mechanism of hot isostatically pressed CrMnFeCoNi high-entropy alloy in high-temperature molten salt environments","authors":"Jiatao Lv , Jiahao Liu , Shuwen Guo , Jing Zhang , Chunyu Chen , Chuanbo Zheng , Zhanfang Wu , Xiangyang Li , Dianchun Ju","doi":"10.1016/j.intermet.2025.109074","DOIUrl":"10.1016/j.intermet.2025.109074","url":null,"abstract":"<div><div>CrMnFeCoNi high-entropy alloy (HEA) was fabricated via hot isostatic pressing (HIP), and its high-temperature corrosion behavior and mechanism in NaCl-KCl molten salts were systematically investigated. The alloy exhibited a single FCC phase with a homogeneous elemental distribution and no noticeable segregation. The corrosion products were mainly identified as Cr<sub>2</sub>O<sub>3</sub>, Mn<sub>2</sub>O<sub>3</sub>, Fe<sub>2</sub>O<sub>3</sub>, Mn<sub>3</sub>O<sub>4</sub>, and MnCr<sub>2</sub>O<sub>4</sub> spinel oxides. At 650 °C and 750 °C, the alloy showed relatively stable surface morphologies, with both weight loss and corrosion rate increasing linearly with time. In contrast, at 850 °C, the surface morphology became more complex, dominated by porous spinel oxides, accompanied by a pronounced acceleration in weight loss and corrosion rate. By performing an Arrhenius fit of the linear rate constant k<sub>l</sub> at multiple temperatures, the activation energy of the linear corrosion process was determined to be 120.4 kJ/mol. Thermodynamic calculations of Gibbs free energy (ΔG) revealed that Mn and Cr possess high reactivity toward O<sub>2</sub> and Cl<sub>2</sub>, leading to the preferential formation of Cr<sub>2</sub>O<sub>3</sub>-, Mn<sub>2</sub>O<sub>3</sub>-, and minor Fe<sub>2</sub>O<sub>3</sub>-rich oxide layers during the early corrosion stage. With prolonged exposure, progressive spallation of the oxide scale facilitated the ingress of molten salts, promoting severe substrate attack, the development of new Cr<sub>2</sub>O<sub>3</sub>- and Mn<sub>2</sub>O<sub>3</sub>-rich layers, internal oxidation, and the formation of increasingly coarse spinel oxides at the alloy surface.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"188 ","pages":"Article 109074"},"PeriodicalIF":4.8,"publicationDate":"2025-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526220","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 : 2025-11-08DOI: 10.1016/j.intermet.2025.109064
Liran Huang , Shiyu Liu , Chenliang Chu , Yubin Ke , Hao Wang , Zhiqiang Fu
The widely used marine materials, nickel aluminum bronzes (NAB), are facing a bottleneck of improving their limited strength and moderate corrosion resistance. In this study, we proposed a novel face-centered cubic (FCC) Cu48Ni17Cr10Al10Co7Fe5Mn3 (at.%) medium-entropy alloy (MEA) strengthened by coherent L12 nanoprecipitates and two types of other secondary phases. One secondary phase exhibited FCC/L12 structure with spinodal decomposition, while the other BCC/B2 phase displayed a core-shell structure. Compared with the typical as-cast NAB, the mechanical properties and corrosion resistance of the as-cast Cu-rich MEA were simultaneously improved. Specifically, its tensile yield strength was increased from ∼343 MPa to ∼564 MPa, total elongation was increased from ∼22.4 % to ∼26.5 %, and corrosion current density was reduced by three orders of magnitude. Our results confirmed that the Cu-rich MEA displays a heretofore unattainable combination of mechanical performance and corrosion resistance when compared to those of previously studied Cu-bearing alloys. This impressive combination of strength and ductility was primarily attributed to the synergistic effect of multiple secondary phases, and outstanding corrosion resistance originated from the stabilized and dense passive film. The results presented here validate the hypothesis that the concept of Cu-rich MEA provides a powerful strategy to enhance the corrosion resistance and mechanical response of conventional Cu-bearing alloys.
{"title":"A Cu-rich medium-entropy alloy with high strength and outstanding corrosion resistance","authors":"Liran Huang , Shiyu Liu , Chenliang Chu , Yubin Ke , Hao Wang , Zhiqiang Fu","doi":"10.1016/j.intermet.2025.109064","DOIUrl":"10.1016/j.intermet.2025.109064","url":null,"abstract":"<div><div>The widely used marine materials, nickel aluminum bronzes (NAB), are facing a bottleneck of improving their limited strength and moderate corrosion resistance. In this study, we proposed a novel face-centered cubic (FCC) Cu<sub>48</sub>Ni<sub>17</sub>Cr<sub>10</sub>Al<sub>10</sub>Co<sub>7</sub>Fe<sub>5</sub>Mn<sub>3</sub> (at.%) medium-entropy alloy (MEA) strengthened by coherent L1<sub>2</sub> nanoprecipitates and two types of other secondary phases. One secondary phase exhibited FCC/L1<sub>2</sub> structure with spinodal decomposition, while the other BCC/B2 phase displayed a core-shell structure. Compared with the typical as-cast NAB, the mechanical properties and corrosion resistance of the as-cast Cu-rich MEA were simultaneously improved. Specifically, its tensile yield strength was increased from ∼343 MPa to ∼564 MPa, total elongation was increased from ∼22.4 % to ∼26.5 %, and corrosion current density was reduced by three orders of magnitude. Our results confirmed that the Cu-rich MEA displays a heretofore unattainable combination of mechanical performance and corrosion resistance when compared to those of previously studied Cu-bearing alloys. This impressive combination of strength and ductility was primarily attributed to the synergistic effect of multiple secondary phases, and outstanding corrosion resistance originated from the stabilized and dense passive film. The results presented here validate the hypothesis that the concept of Cu-rich MEA provides a powerful strategy to enhance the corrosion resistance and mechanical response of conventional Cu-bearing alloys.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"188 ","pages":"Article 109064"},"PeriodicalIF":4.8,"publicationDate":"2025-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474512","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 : 2025-11-07DOI: 10.1016/j.intermet.2025.109069
Haipeng Zhou , Daming Tong , Rui Wang , Yecong Shen , Lizhan Han , Jianfeng Gu
A phase-field model (PFM) for the precipitation of γ′ phases in nickel-based single crystal superalloys (Ni-SXs) during aging process is established, with DD10 alloy used as the research object, and the precipitation and evolution of γ′ phase during aging are simulated. The reliability of the model is confirmed through quantitative comparison with experimental results. The average errors between the simulated and experimental results for the γʹ precipitates volume fraction, size, and number after aging at 1143 K, 1273 K, and 1393 K are 20.86 %, 8.58 %, and 10.5 %, respectively. Based on the proposed model, the microstructure evolution under different aging conditions is simulated to analyze the effects of elastic energy and temperature on the precipitation kinetics, concentration fields, and stress-strain distributions within γ′ phase microstructure. The results indicate that the growth process of the γʹ precipitates during aging can be divided into a rapid growth stage and a ripening growth stage. The relationship between the number, size, and time of the γʹ precipitates can all be fitted using a power function. The average stress firstly increases and then decreases during aging process. The Al concentrations within both the γʹ phase and the γ matrix are relatively uniform, with the concentration in the γʹ phase significantly higher than that in the γ matrix. The Al concentration, stress and strain at the interface are slightly higher. Elastic energy exerts an inhibitory effect on Ostwald ripening, while temperature promotes the growth of the γʹ precipitates. Elastic energy slows down the variation of the number and average size of γʹ precipitates, whereas higher temperatures accelerate these processes.
{"title":"Phase-field study on effects of elastic energy and aging temperature on precipitation kinetics of γ′ phase in nickel-based superalloys","authors":"Haipeng Zhou , Daming Tong , Rui Wang , Yecong Shen , Lizhan Han , Jianfeng Gu","doi":"10.1016/j.intermet.2025.109069","DOIUrl":"10.1016/j.intermet.2025.109069","url":null,"abstract":"<div><div>A phase-field model (PFM) for the precipitation of γ′ phases in nickel-based single crystal superalloys (Ni-SXs) during aging process is established, with DD10 alloy used as the research object, and the precipitation and evolution of γ′ phase during aging are simulated. The reliability of the model is confirmed through quantitative comparison with experimental results. The average errors between the simulated and experimental results for the γʹ precipitates volume fraction, size, and number after aging at 1143 K, 1273 K, and 1393 K are 20.86 %, 8.58 %, and 10.5 %, respectively. Based on the proposed model, the microstructure evolution under different aging conditions is simulated to analyze the effects of elastic energy and temperature on the precipitation kinetics, concentration fields, and stress-strain distributions within γ′ phase microstructure. The results indicate that the growth process of the γʹ precipitates during aging can be divided into a rapid growth stage and a ripening growth stage. The relationship between the number, size, and time of the γʹ precipitates can all be fitted using a power function. The average stress firstly increases and then decreases during aging process. The Al concentrations within both the γʹ phase and the γ matrix are relatively uniform, with the concentration in the γʹ phase significantly higher than that in the γ matrix. The Al concentration, stress and strain at the interface are slightly higher. Elastic energy exerts an inhibitory effect on Ostwald ripening, while temperature promotes the growth of the γʹ precipitates. Elastic energy slows down the variation of the number and average size of γʹ precipitates, whereas higher temperatures accelerate these processes.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"188 ","pages":"Article 109069"},"PeriodicalIF":4.8,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474511","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 : 2025-11-07DOI: 10.1016/j.intermet.2025.109058
Leshen Chang , Xiaojun Sun , Dunbo Yu , Xuexu Gao , Xiaoqian Bao , Weiguo Gao , Xiao Lin , Zilong Wang , Wenlong Yan , Yang Luo
An important idea for the fabrication of high coercivity Nd-Fe-Ga-B magnets is the careful tuning of the Nd6Fe13Ga intergranular phase. However, the influence of other Nd-Fe-Ga ternary compounds in the grain boundaries on the microstructure and magnetic properties of magnets remains underexplored, and the related mechanisms are still unclear. In this study, the Nd2Fe15Ga2 phase was found as the precursor phase of the Nd6Fe13Ga phase in Nd-Fe-Ga-B magnets by adjusting the annealing process. The results show that the coercivity of magnets containing Nd2Fe15Ga2 phase is about 0.5 kOe higher than those containing Nd6Fe13Ga phase. Moreover, the mechanism of coercivity enhancement and phase transition between the Nd2Fe15Ga2 phase and the Nd6Fe13Ga phase was investigated. Comparing the magnets containing two different grain boundary phases, the generation of the Nd2Fe15Ga2 phase allows more Fe elements to be enriched in the triangular grain boundary region and consumes less rare earth elements. The grain boundary phase of the magnet, containing the Nd2Fe15Ga2 phase, exhibits a reduced saturation magnetization. This diminished saturation magnetization has a more pronounced effect on the reduction of exchange coupling between the main phase grains. As a result, it leads to a significant enhancement in the coercivity of the magnet associated with the Nd2Fe15Ga2 phase. This study provides a novel approach to regulating magnet grain boundary phases, along with new insights and theoretical guidance for the development of heavy rare-earth-free magnets.
{"title":"A new Nd2Fe15Ga2 phase - Driven grain boundary engineering: A breakthrough for high-coercivity Ga-doped Nd-Fe-B magnets","authors":"Leshen Chang , Xiaojun Sun , Dunbo Yu , Xuexu Gao , Xiaoqian Bao , Weiguo Gao , Xiao Lin , Zilong Wang , Wenlong Yan , Yang Luo","doi":"10.1016/j.intermet.2025.109058","DOIUrl":"10.1016/j.intermet.2025.109058","url":null,"abstract":"<div><div>An important idea for the fabrication of high coercivity Nd-Fe-Ga-B magnets is the careful tuning of the Nd<sub>6</sub>Fe<sub>13</sub>Ga intergranular phase. However, the influence of other Nd-Fe-Ga ternary compounds in the grain boundaries on the microstructure and magnetic properties of magnets remains underexplored, and the related mechanisms are still unclear. In this study, the Nd<sub>2</sub>Fe<sub>15</sub>Ga<sub>2</sub> phase was found as the precursor phase of the Nd<sub>6</sub>Fe<sub>13</sub>Ga phase in Nd-Fe-Ga-B magnets by adjusting the annealing process. The results show that the coercivity of magnets containing Nd<sub>2</sub>Fe<sub>15</sub>Ga<sub>2</sub> phase is about 0.5 kOe higher than those containing Nd<sub>6</sub>Fe<sub>13</sub>Ga phase. Moreover, the mechanism of coercivity enhancement and phase transition between the Nd<sub>2</sub>Fe<sub>15</sub>Ga<sub>2</sub> phase and the Nd<sub>6</sub>Fe<sub>13</sub>Ga phase was investigated. Comparing the magnets containing two different grain boundary phases, the generation of the Nd<sub>2</sub>Fe<sub>15</sub>Ga<sub>2</sub> phase allows more Fe elements to be enriched in the triangular grain boundary region and consumes less rare earth elements. The grain boundary phase of the magnet, containing the Nd<sub>2</sub>Fe<sub>15</sub>Ga<sub>2</sub> phase, exhibits a reduced saturation magnetization. This diminished saturation magnetization has a more pronounced effect on the reduction of exchange coupling between the main phase grains. As a result, it leads to a significant enhancement in the coercivity of the magnet associated with the Nd<sub>2</sub>Fe<sub>15</sub>Ga<sub>2</sub> phase. This study provides a novel approach to regulating magnet grain boundary phases, along with new insights and theoretical guidance for the development of heavy rare-earth-free magnets.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"188 ","pages":"Article 109058"},"PeriodicalIF":4.8,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474258","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 : 2025-11-07DOI: 10.1016/j.intermet.2025.109075
Sitao Wei , Jie Gao , Xu Liu , Lin Song , Daria Lazurenko , Yongfeng Liang , Tiebang Zhang , Junpin Lin
Wrought Ti2AlNb alloy is a promising key structural material for reducing the weight of aero-engines. The study of the high temperature deformation behavior of the alloy is crucial for optimizing its hot working process. In this study, the phase transformation and load partitioning of the α2, O and B2 phases in Ti2AlNb alloys during deformation are investigated by in-situ synchrotron high-energy X-ray diffraction (HEXRD). During compression at 1050 °C, the α2 phase transforms into B2 phase under a stress of ∼59.4 MPa. During compression at 800 °C, the O phase transforms to B2 phase under a stress of ∼557 MPa. Stress partitioning behavior during compression at 800 °C are studied for O and B2 phases. Beyond the elastic deformation stage, the plastic deformation first initiates in the B2 phase while the O phase mainly deforms elastically. In parallel, load partitioning occurs between these two phases. The von Mises stress of the O phase can be as high as 3 times than that of the B2 phase. Consequently, high internal stresses are accumulated in the O phase.
{"title":"In-situ synchrotron HEXRD study on phase transformation and microscopic deformation of a Ti2AlNb alloy during high-temperature compression","authors":"Sitao Wei , Jie Gao , Xu Liu , Lin Song , Daria Lazurenko , Yongfeng Liang , Tiebang Zhang , Junpin Lin","doi":"10.1016/j.intermet.2025.109075","DOIUrl":"10.1016/j.intermet.2025.109075","url":null,"abstract":"<div><div>Wrought Ti<sub>2</sub>AlNb alloy is a promising key structural material for reducing the weight of aero-engines. The study of the high temperature deformation behavior of the alloy is crucial for optimizing its hot working process. In this study, the phase transformation and load partitioning of the α<sub>2</sub>, O and B2 phases in Ti<sub>2</sub>AlNb alloys during deformation are investigated by in-situ synchrotron high-energy X-ray diffraction (HEXRD). During compression at 1050 °C, the α<sub>2</sub> phase transforms into B2 phase under a stress of ∼59.4 MPa. During compression at 800 °C, the O phase transforms to B2 phase under a stress of ∼557 MPa. Stress partitioning behavior during compression at 800 °C are studied for O and B2 phases. Beyond the elastic deformation stage, the plastic deformation first initiates in the B2 phase while the O phase mainly deforms elastically. In parallel, load partitioning occurs between these two phases. The von Mises stress of the O phase can be as high as 3 times than that of the B2 phase. Consequently, high internal stresses are accumulated in the O phase.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"188 ","pages":"Article 109075"},"PeriodicalIF":4.8,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474254","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 hot deformation behavior of Al0.3Co1.5CrFeNi1.5Ti0.2 high-entropy alloy was studied at temperatures and strain rates varying from 923 to 1373 K and 10−3 to , respectively. A constitutive equation was formulated to characterize material flow within these conditions and predict its behavior under similar or extended conditions. Stress exponent and deformation activation energy were determined to be 4.44 and ∼490 kJ/mol, respectively, suggesting that the material undergoes high-temperature deformation primarily controlled by dislocation climb. Moreover, at 923 K, the power law breakdown was observed, with no flow softening occurring up to a true strain of 0.5. The processing map identified optimal deformation conditions, achieving highest efficiency (∼34 %), at strain rates of , and temperatures 1300 K. Instability domain (strain rate range: , temperatures: 923–1165 K), was characterized by presence of voids and cracks. Further, transmission electron microscopy study highlighted the dynamic development of L12, B2 and σ phases at different temperatures and identified their correlation with instability domains in the processing map. The predominant deformation mechanisms were identified as dislocation climb and discontinuous dynamic recrystallization (DDRX). Electron back scattered diffraction microstructural investigations confirmed the occurrence of DDRX.
{"title":"Hot deformation behavior and processing map development of Al0.3Co1.5CrFeNi1.5Ti0.2 high-entropy alloy: Mechanisms and microstructural evolution","authors":"Bushra Harun , Ranjeet Kumar , Shubham Jaiswal , E-Wen Huang , Yao-Jen Chang , An-Chou Yeh , Sudhanshu Shekhar Singh , Suresh Neelakantan , Jayant Jain","doi":"10.1016/j.intermet.2025.109071","DOIUrl":"10.1016/j.intermet.2025.109071","url":null,"abstract":"<div><div>The hot deformation behavior of Al<sub>0.3</sub>Co<sub>1.5</sub>CrFeNi<sub>1.5</sub>Ti<sub>0.2</sub> high-entropy alloy was studied at temperatures and strain rates varying from 923 to 1373 K and 10<sup>−3</sup> to <span><math><mrow><mn>1</mn><mspace></mspace><msup><mi>s</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>, respectively. A constitutive equation was formulated to characterize material flow within these conditions and predict its behavior under similar or extended conditions. Stress exponent and deformation activation energy were determined to be 4.44 and ∼490 kJ/mol, respectively, suggesting that the material undergoes high-temperature deformation primarily controlled by dislocation climb. Moreover, at 923 K, the power law breakdown was observed, with no flow softening occurring up to a true strain of 0.5. The processing map identified optimal deformation conditions, achieving highest efficiency (∼34 %), at strain rates of <span><math><mrow><mn>0.03</mn><mo>−</mo><mn>1</mn><mspace></mspace><msup><mi>s</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>, and temperatures <span><math><mrow><mo>></mo></mrow></math></span> 1300 K. Instability domain (strain rate range: <span><math><mrow><mn>0.01</mn><mo>−</mo><mn>1</mn><mspace></mspace><msup><mi>s</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>, temperatures: 923–1165 K), was characterized by presence of voids and cracks. Further, transmission electron microscopy study highlighted the dynamic development of L1<sub>2</sub>, B2 and σ phases at different temperatures and identified their correlation with instability domains in the processing map. The predominant deformation mechanisms were identified as dislocation climb and discontinuous dynamic recrystallization (DDRX). Electron back scattered diffraction microstructural investigations confirmed the occurrence of DDRX.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"188 ","pages":"Article 109071"},"PeriodicalIF":4.8,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474260","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 : 2025-11-06DOI: 10.1016/j.intermet.2025.109072
Chenyang Zhang , Xiaoqin Liang , Zhen Wang , Yanxun Mu , Shuai Wang , Yikun Su , Xu Ning , Chunyang Peng , Yuchen Mao , Yongfeng Liang , Junpin Lin
The excellent soft magnetic properties of high-silicon steel are hindered by its intrinsic brittleness, which impedes the large-scale production and processing of ultra-thin strips. This study demonstrates the effective use of rapid solidification technology through planar flow casting, enabling the continuous production of flexible high-silicon steel. Optimization of processing parameters yielded a multiscale structure with surface fine grains (∼2 μm), internal <100>-oriented columnar cell crystals (400–600 nm), and coherently precipitated B2 structures with low ordering degree (<10 nm). Design simultaneously enhances the magnetic and mechanical properties of the ribbons. Despite the presence of a high density of defects and internal stresses, it achieves a room-temperature elongation of 2.54 % while maintaining high magnetic induction. The ribbons can be continuously punched and rolled at room temperature, providing an efficient, cost-effective solution for their manufacture.
{"title":"Enhancement of room-temperature ductility in high silicon steel ribbons through disordering and microstructural refinement","authors":"Chenyang Zhang , Xiaoqin Liang , Zhen Wang , Yanxun Mu , Shuai Wang , Yikun Su , Xu Ning , Chunyang Peng , Yuchen Mao , Yongfeng Liang , Junpin Lin","doi":"10.1016/j.intermet.2025.109072","DOIUrl":"10.1016/j.intermet.2025.109072","url":null,"abstract":"<div><div>The excellent soft magnetic properties of high-silicon steel are hindered by its intrinsic brittleness, which impedes the large-scale production and processing of ultra-thin strips. This study demonstrates the effective use of rapid solidification technology through planar flow casting, enabling the continuous production of flexible high-silicon steel. Optimization of processing parameters yielded a multiscale structure with surface fine grains (∼2 μm), internal <100>-oriented columnar cell crystals (400–600 nm), and coherently precipitated B2 structures with low ordering degree (<10 nm). Design simultaneously enhances the magnetic and mechanical properties of the ribbons. Despite the presence of a high density of defects and internal stresses, it achieves a room-temperature elongation of 2.54 % while maintaining high magnetic induction. The ribbons can be continuously punched and rolled at room temperature, providing an efficient, cost-effective solution for their manufacture.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"188 ","pages":"Article 109072"},"PeriodicalIF":4.8,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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