Abstract
The chemical boundaries inside the ultrafine spinodal decomposition structure in metastable β-Ti al-loys 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.Utiliz-ing the spinodal decomposition structure,the aged Ti-Al-Mo-V-Cr-Zr alloys showed multi-architecturedα precipitates spanning from micron-scale(primary αp)to nano-scale(secondary αs)that were uni-formly distributed in the β-domains.Being compared with the forged sample,the multi-scale heteroge-neous 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 ap-proach 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.
基金项目
National Natural Science Foundation of China(92163201)
National Natural Science Foundation of China(U2067219)
Shaanxi Province Youth Innovation Team Project(22JP042)
Shaanxi Province Innovation Team Project(2024RS-CXTD-58)
Fundamental Research Funds for the Central Universities(xtr022019004)
NETL
NSTL
万方数据