Microstructure and Mechanical Properties of a' Martensite Type Ti-V-Al Alloy after Cold- or Hot Working Process

摘要

Ti alloys are widely utilized for industrial applications due to their excellent mechanical properties combined with low density. In general, Ti alloys are classified as α, α+β and β alloys, with further subdivision into near α and metastable β alloys. Quite recently, we have presented new type structural a' martensite (H.C.P.) Ti alloys with low Young's modulus, high strength and excellent ductility at room temperature. In this work, we examined the microstructure and mechanical properties of a' martensite type Ti-V-Al alloy after cold- or hot working process. Then, we found that deformation behavior of a' initial microstructure as compared with (α+β) initial microstructure was different based on the results of stress-strain curves and Processing Maps under the hot working process. Further, cold rolled a' martensite microstructure exhibited the refined equiaxed dislocation cell structure, thereby resulting in high strength. This result suggests the new type deformation processing (for both cold- and hot work processing) utilizing a' martensite in industrial Ti alloys.