Spinodal decomposition-me diate d multi-architectured α precipitates making a metastable β-Ti alloy ultra-strong and ductile  

作　　者：J.K.Yang C.L.Zhang H.Zhang J.Li J.Y.Zhang J.Kuang G.Liu J.Sun 

机构地区：[1]State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China

出　　处：《Journal of Materials Science & Technology》2024年第24期106-121,共16页材料科学技术(英文版)

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.92163201 and U2067219);Shaanxi Province Youth Innovation Team Project(No.22JP042);Shaanxi Province Innovation Team Project(No.2024RS-CXTD-58);the Fundamental Research Funds for the Central Universities(No.xtr022019004).

摘　　要：The chemical boundaries inside the ultrafine spinodal decomposition structure in metastable β-Ti alloys can act as a new feature to architect heterogeneous microstructures.In this work,we combined two semi-empirical methods,i.e.,the d-electron theory and the e/a electron concentration,to achieve the spinodal decomposition structure in a metastable β Ti-4.5Al-4.5Mo-7V-1.5Cr-1.5Zr(wt.%)alloy.Utilizing the spinodal decomposition structure,the aged Ti-Al-Mo-V-Cr-Zr alloys showed multi-architectured α precipitates spanning from micron-scale(primary α_(p))to nano-scale(secondary α_(s))that were uniformly distributed in the β-domains.Being compared with the forged sample,the multi-scale heterogeneous microstructure enables the aged β-Ti alloy to have ultra-high strength(yield strength ~1366 MPa and ultimate tensile strength ~1424 MPa)and an appreciable ductility(~9.3%).Strengthening models were proposed for the present alloys to estimate the contribution of various microstructural features to the measured yield strength.While the solid solution strengthening,β-spinodal strengthening,and back stress strengthening made comparable contributions to the strength of the forged alloy,the back stress strengthening was the predominant strengthening effect in the aged alloy.This alloy design approach based on chemical boundary engineering to construct multi-architectured α precipitates provided an effective strategy for achieving an outstanding combination of ultra-high strength and ductility in metastable β-Ti alloys.

关 键 词：Ti alloys Multi-architecturedαprecipitates Spinodal decomposition Mechanical properties Strengthening mechanisms 

分 类 号：TG146.23[一般工业技术—材料科学与工程]