Microstructure and mechanical properties of a high-oxygen core-shell network structured Ti6Al4V alloy. (March 2018)

• Record Type: Journal Article
• Authors: Zhang, Y.S.; Hu, J.J.; Zhao, Y.Q.; Bai, X.F.; Huo, W.T.; Zhang, W.; Zhang, L.C.
• Is Part Of: Vacuum. Volume 149(2018)
• Page Start: 140
• Page End: 145
• Publication Date: 2018-03
• Subjects: Core-shell -- Sintering -- Strength -- Ti alloys; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2017.12.036
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: Fully dense core-shell (CS) structured Ti-6Al-4V (Ti64) compact was synthesized by spark plasma sintering (SPS) from oxidized Ti64 powder. Microstructure characterization and compositional analyses show that the shell is with near single α phase and the core is composed of α lamellae packed by β phase with a continuous β phase in between. Phase transformation from (α+β) phase to a near single α phase in shell is attributed to oxygen penetration, thereby forming such a novel CS structure. The CS Ti64 compact exhibits a yield strength of about 1260 MPa and a fracture elongation of 13%. Such excellent mechanical properties are attributed to solid strengthening of oxygen and the unique core-shell structure. The mechanical properties can be further enhanced by manipulating the microstructure in core and shell via heat treatment. Highlights: A novel core-shell structure is introduced in a dual phase Ti alloy. Shell is α phase and core is α+β phase with β plate in between them. Formation of single α phase in shell results in the unique structure. A good combination of mechanical performance is obtained.