Microstructures of brazing zone between titanium alloy and stainless steel using various filler metals

Abstract

Titanium alloy (Ti–Al–V alloy) substrate was brazed with stainless steel (STS304) using filler metal. At an optimized brazing condition, various filler metals were used. Microstructures were observed at each condition. Filler metals were titanium based 40Ti–20Zr–20Cu–20Ni, silver based Ag–5Pd, and nickel based Ni–7Cr–3.1B–4.5Si–3Fe–0.06C (BNi2) and Ni–14Cr–10P–0.06C (BNi7). To select a good filler metal for brazing process, wetting test was performed at 880–1050 °C. It was not brazed using silver based filler metals, but at the conditions using titanium and nickel based filler metals had brazed zone between titanium alloy and stainless steel. However, titanium alloy was eroded during brazing using titanium based filler metals. Nickel based filler metal has a good brazed zone between titanium alloy and stainless steel among the filler metals.