Microstructure and properties of ZrO2 ceramic and Ti-6A-4V alloy vacuum brazed by Ti-28Ni filler metal

Abstract

Reliable ceramics/metal joints have an extensive application in the aerospace and biomedical area. However, ZrO2ceramic has not been investigated systematically compared to the Si3N4and Al2O3ceramic. Therefore, successful brazing of ZrO2ceramic and Ti-6A-4V alloy was achieved by using a binary active Ti-28Ni filler metal in this paper. The effect of holding time on the microstructure of ZrO2 ceramic/filler metal interface and mechanical properties of brazed joints was investigated. The results indicated that the representative interfacial microstructure was ZrO2ceramic/Ti2O/Ni2Ti4O/Ti-rich phase/Ti2Ni+α-Ti. With the increase of holding time, the thickness of Ti-rich layer in the interface of ZrO2/Ti-6Al-4Vjoint decreased obviously due to the diffusion of Ti atoms. Substantial brittle intermetallic compounds Ti2Ni and Ni2Ti4O were formed in the joint, which were detrimental to the mechanical properties of the brazed joints. The maximum shear strength of joint was 112.7 MPa when brazed at 1060 °C for 10 min.