Intermetallics最新文献

{"title":"Effects of 800°C NaCl salt-spray corrosion on fracture behavior and deformation mechanism in a NiCoCr-based superalloy","authors":"Zhongfeng Chen ,&nbsp;Anping Dong ,&nbsp;Zhengye Zhang ,&nbsp;Lin He ,&nbsp;Dafan Du ,&nbsp;Lianghua Xiong ,&nbsp;Yunwei Pan","doi":"10.1016/j.intermet.2025.109013","DOIUrl":"10.1016/j.intermet.2025.109013","url":null,"abstract":"<div><div>NiCoCr-based superalloys operating in marine environments are subjected to severe corrosion, which can significantly affect their mechanical performance. In this study, a systematic investigation is carried out to elucidate the effects of NaCl salt-spray exposure at 800 °C on fracture behavior and deformation mechanisms of a newly developed γ′-strengthened NiCoCr-based superalloy, K439B. The tensile tests reveal a degradation of mechanical performance after NaCl salt-spray exposure at 800 °C for 70 h: the ultimate tensile strength (UTS) decreases from 1113 MPa to 816 MPa, and the elongation at break (EL) drops from 6.0 % to 1.2 %. Fracture morphologies show that the uncorroded specimen exhibits mixed ductile-brittle fracture features with quasi-cleavage facets, ductile dimples, and slip-band evidence, whereas the corroded specimen develops a corrosion-affected zone at the fracture edge, containing a high density of corrosion-induced voids. These voids are considered as crack initiation sites and stress concentrators, promoting brittle failure. Elemental distribution within the corrosion-affected zone reveals the depletion of Cr and γ′-forming elements (<em>e.g.</em>, Al, Ti), and the local stress concentrations adjacent to corrosion voids are observed. In addition, the uncorroded specimen deforms primarily by planar slip and stacking fault cutting γ′ phase, while the corroded specimen shows dense dislocation tangling around corrosion voids and pile-up at the grain boundary and around the Al oxides, leading to the significant decrease in ductility. The results show mechanical degradation and altered deformation mechanisms in K439B alloy after NaCl salt-spray exposure at 800 °C, offering critical insights for evaluating its service performance in high-temperature marine environments.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 109013"},"PeriodicalIF":4.8,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145156002","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":"Unravelling formation mechanism, phase stability and transitions of metastable α2 and B2 phases in laser additively manufactured Ti-48Al-2Cr-2Nb alloy","authors":"Maosong Wang,&nbsp;Haojie Luo,&nbsp;Aoqi Fan,&nbsp;Yulei Du","doi":"10.1016/j.intermet.2025.109012","DOIUrl":"10.1016/j.intermet.2025.109012","url":null,"abstract":"<div><div>The solidification route and microstructure evolution of TiAl alloys are strongly dependent on cooling rate, leading to a significant presence of ordered α₂ and B2 phases in those fabricated using laser powder bed fusion (LPBF). However, the formation mechanisms, thermal stability and decomposition behaviors of this special phase composition remain unclear. In this work, we studied a Ti-48Al-2Cr-2Nb alloy fabricated by LPBF to understand its unique ordered phase structure. It was found that both the high-temperature α and β phases can nucleate and grow from the liquid TiAl, and subsequently transform to metastable α₂ and B2 phases through ordered transition. The minimum cooling rate for the transition of <em>β→B2</em> was determined as 3.28 × 10⁴ K/s, with the content of the B2 phase increasing at higher cooling rate. Based on in-situ characterization and annealing treatment, both the ordered α₂ and B2 phases were revealed to exhibit weak thermal stability, which were attributed to their special chemical composition deviated from that in equilibrium solidification due to insufficient atomic diffusion. This phenomenon also results in the formation of disordered γ phase and early precipitation of high-temperature α and β phases during heat treatment. This study provides valuable insights into the microstructural characteristic of Ti-48Al-2Cr-2Nb alloys fabricated at high cooling rate, offering guidance for the LPBF building and post heat treatment process.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 109012"},"PeriodicalIF":4.8,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155336","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":"Development of L12 nanoparticles strengthened Ni-Co-Al-Ta based superalloys with excellent comprehensive properties","authors":"Haojun Zhuo ,&nbsp;Debin Zheng ,&nbsp;Chen Yang ,&nbsp;Yihui Guo ,&nbsp;Jiajia Han ,&nbsp;Cuiping Wang ,&nbsp;Xingjun Liu","doi":"10.1016/j.intermet.2025.109007","DOIUrl":"10.1016/j.intermet.2025.109007","url":null,"abstract":"<div><div>This study addresses a critical research gap by pioneering a systematic alloy design in the Co-Ni-Al-Ta system, leveraging a thermodynamic database and CALPHAD method to optimize Ni content, leading to the development of a novel Co-45Ni-12Al-4Ta-2W superalloy with exceptional properties. Key innovations include the identification of an optimal Co-45Ni-12Al-4Ta master alloy and comprehensive analysis of γ′-forming elements (Mo, V, W, Ti, Nb), which revealed that W addition achieves an optimal balance between different properties: intermediate γ′/γ misfit (1.08 %) and low coarsening rate ((1.07 ± 0.07) × 10⁻²⁷ m³/s), coupled with unprecedented thermal stability (γ′ solvus at 1250 °C and solidus at 1372 °C). Remarkably, this alloy demonstrates anomalous strengthening at 650 °C, yielding compressive strengths of 1059 ± 32 MPa (RT), 1060 ± 31 MPa (650 °C), and 668 ± 21 MPa (900 °C), highlighting its potential for next-generation aerospace materials through further optimization.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 109007"},"PeriodicalIF":4.8,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155337","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":"Integrated design of superhydrophobic structures and photocatalytic functions of Zr46Cu46Al8 metallic glass surfaces","authors":"Guanzhong Ding ,&nbsp;Guoyang Zhang ,&nbsp;Ranfeng Wei ,&nbsp;Yujia Wang ,&nbsp;Rui Zheng ,&nbsp;Qijing Sun ,&nbsp;Jingwang Lv ,&nbsp;Haipeng Wang ,&nbsp;Dan Li ,&nbsp;Paul K. Chu ,&nbsp;Li Liu ,&nbsp;Xiangjin Zhao","doi":"10.1016/j.intermet.2025.109009","DOIUrl":"10.1016/j.intermet.2025.109009","url":null,"abstract":"<div><div>Metallic glasses have considerable potential in applications such as wastewater degradation, but the corrosion resistance and catalytic degradation performance require improvement. Herein, this study presents a simple electrochemical strategy that simultaneously improves the superhydrophobic properties of the cathode and anode surfaces by using Zr₄₆Cu₄₆Al₈ metallic glass as the cathode and anode substrates. The etched surface on the anode comprises a micro-nanometer composite coating of ZrO₂/CuO/Cu₂O, while the cathode surface has a micro-nanometer composite structure of CuO/Cu₂O/Fe₂O₃. The composite oxides produce enhanced catalytic degradation characteristics on the substrate. The micro-nanometer structures formed on the metallic glass surface give rise to superhydrophobicity, which improves the corrosion resistance and adaptability to complex environments. Furthermore, the stability and cyclic degradation capability are excellent, boding well for industrial implementation. Our results reveal a novel strategy to improve both the structure and functions of metallic glasses for different applications such as wastewater treatment.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 109009"},"PeriodicalIF":4.8,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119222","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":"Laser-deposited CoCrFeNiTiAlx high-entropy alloy coatings featuring balanced wear and corrosion resistance","authors":"Fengyuan Shu ,&nbsp;Jia Deng ,&nbsp;Hua Yang ,&nbsp;Xin Zhang ,&nbsp;Zhuqiang Xiang ,&nbsp;Jie Wang ,&nbsp;Guibian Li ,&nbsp;Yuzhong Ren ,&nbsp;Bing Lei ,&nbsp;Xin Yuan","doi":"10.1016/j.intermet.2025.109004","DOIUrl":"10.1016/j.intermet.2025.109004","url":null,"abstract":"<div><div>CoCrFeNiTiAl_x (x = 0, 0.5, 0.75, 1.0) high-entropy alloy (HEA) coatings were fabricated by laser deposition (LD) technology and the effect of Al content in microstructure-property relationships was systematically investigated. The HEA coatings contain face-centered cubic(FCC) and body-centered cubic(BCC) structure, with ordered B2-type Al-Ni compounds emerging at x = 1. Increasing Al content promoted a progressive FCC to BCC phase transformation accompanied by lattice distortion and grain refinement. Notably, Al addition significantly improved coating formability by suppressing crack initiation during LD processes through its deoxidizing reduction and slagging capabilities, which optimized melt fluidity and minimized structural defects such as pores and cracks. The microhardness exhibited a 44 % enhancement (616.12  →  887.26 HV) with gradually Al increase, attributed to synergistic BCC phases, solid solution and Hall-Petch refinement strengthening. The average coefficient of friction and wear rate of the coatings both showed a decreasing trend, specifically an 83 % reduction in wear rate (14.12  →  2.42 × 10⁻⁵ mm³/N·m) at x = 0.75. Al addition converted the wear mechanism from adhesive-abrasive wear to oxidative wear via in-situ formation of Al₂O₃/Cr₂O₃ tribofilms. Al alloying also enhanced the corrosion resistance of the HEAs. The Al₁ coating exhibited the lowest I_corr (8.72 μA/cm²) and highest charge-transfer resistance(R_ct). These properties are attributed to the formation of denser and more stable Cr₂O₃ and TiO₂ passive film, which hindered the Cl⁻ transport and strengthened the anti-corrosion mechanism. The Al₁ coating exhibited the optimal comprehensive performance, which provided guidance for designing Al-containing HEAs with balanced corrosion resistance and mechanical performance.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 109004"},"PeriodicalIF":4.8,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119223","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 and Toughness of SiCf/SiC joints though Zr-induced Core-Shell Microstructure evolution in high entropy brazing fillers","authors":"Heng Shao ,&nbsp;Haiyan Chen ,&nbsp;Peng Wang ,&nbsp;Shuai Zhao ,&nbsp;Zhaoyi Pan ,&nbsp;Yongsheng Liu ,&nbsp;Xiaoguo Song ,&nbsp;Pengcheng Wang ,&nbsp;Weimin Long ,&nbsp;Wenya Li","doi":"10.1016/j.intermet.2025.109010","DOIUrl":"10.1016/j.intermet.2025.109010","url":null,"abstract":"<div><div>This study utilizes (FeCoNiCrCu)_100-X Zr_X (X = 10, 15) high-entropy brazing alloys to enable reliable joining of SiC_f/SiC composites to Zr using a vacuum brazing furnace. Microscopic analysis shows that increasing the Zr content to 15 at% significantly improves the wettability of the brazing alloy and promotes the formation of a distinctive “ZrCrFe core–Zr₂Cu shell” microstructure. Compared with the ZrCrFe phase, the Zr₂Cu phase exhibits enhanced plastic deformation capacity. After encapsulating the brittle ZrCrFe phase, it promotes the formation of a region near the SiC_f/SiC interface dominated by plastic FCC phases and Zr₂Cu phases. The Zr₂Cu phase exhibits a coherent crystallographic orientation with the FCC matrix phase, indicating a relatively low lattice mismatch. The wrapped structure contributes to joint toughening through two primary mechanisms: (1) it prevents direct contact between the brittle ZrCrFe phase and the SiC_f/SiC composite, thereby mitigating crack initiation; and (2) it alleviates residual stress concentrations at the ZrCrFe–FCC interface caused by lattice mismatch, enhancing the overall plastic deformation capacity. Finally, the shear strength of the joint containing 15 at% Zr reached 78.61 MPa, representing a 22.4 % increase compared to the specimen containing 10 at% Zr, and indicating enhanced plastic deformation capacity and overall joint strength.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 109010"},"PeriodicalIF":4.8,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119221","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 Ta addition on microstructure, compression and wear properties of CoCrNiTax medium entropy alloys","authors":"Qing Xu ,&nbsp;Senqi Qu ,&nbsp;Xiaojing Xu ,&nbsp;Chenglong Zhao ,&nbsp;Cheng Ai ,&nbsp;Yi Ru ,&nbsp;Heng Zhang ,&nbsp;Shusuo Li ,&nbsp;Shengkai Gong ,&nbsp;Min Guo ,&nbsp;Taiwen Huang ,&nbsp;Lin Liu","doi":"10.1016/j.intermet.2025.109011","DOIUrl":"10.1016/j.intermet.2025.109011","url":null,"abstract":"<div><div>Effect of Ta content on microstructure and mechanical properties of CoCrNiTa_<em>x</em> medium entropy alloys (<em>x</em> = 0.1–0.5) was discussed. With increasing Ta content, CoCrNiTa_<em>x</em> alloys changed from hypoeutectic (<em>x</em> = 0.1, 0.3) to eutectic (<em>x</em> = 0.35) and to hypereutectic (<em>x</em> = 0.4, 0.5) alloys, and CoCrNiTa_<em>x</em> alloys were all composed by γ phase and C14-type Laves phase. Meanwhile, microhardness of CoCrNiTa_<em>x</em> alloys increased with increasing Ta content. With increasing Ta content, compressive strengths of CoCrNiTa_<em>x</em> alloys firstly increased and then decreased, and CoCrNiTa_0.35 alloy had the highest compression strength (2852 MPa). Nanohardness of primary γ phase was much lower than that of primary Laves phase, and nanohardness of eutectic phases firstly increased and then decreased with increasing Ta content. In addition, nanohardness of γ phase in CoCrNiTa_<em>x</em> alloy was higher than that of γ phase in CoCrFeNiTa_<em>x</em> alloy, which provided a notable contribution to compression strengths of CoCrNiTa_<em>x</em> alloys. Wear mechanism gradually changed from adhesive wear to abrasive wear with increasing Ta content, and CoCrNiTa_0.5 alloy exhibited the highest wear resistance.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"187 ","pages":"Article 109011"},"PeriodicalIF":4.8,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119220","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":"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}