(1. School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048, China) (2. Northwest Institute for Nonferrous Metal Research, Xi’an 710016, China) (3. School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024,China)
Complete densified core-shell (CS) structured Ti-6Al-4V (TC4) compact was synthesized by powders nitriding and subsequent spark plasma sintering (SPS). The microstructure and mechanical properties of CS-TC4 after solution treatment and ageing were investigated. The cross-section microstructures of nitrided TC4 powder and sintered core-shell (CS) structured TC4 compact were characterized by optical microscopy (OM) and scanning electron microscope (SEM). The mechanical properties of compacts were also measured. Results show that the shell consists of near single α phase and the core is mainly composed of α laths and β lamellae. Phase transformation from (α+β) phase to a near single α phase in shell is attributed to the nitrogen diffusion, which results in such a novel CS structure. The CS -TC4 compact exhibits yield strength of about 1180 MPa and a fracture elongation of 10%. Such excellent mechanical properties should be attributed to the solid strengthening of nitrogen and the unique core-shell structure. The mechanical properties can be further enhanced through solution and aging treatment for a reasonable microstructure controlling.