抄録
This research has been performed in order to develop a titanium alloy which had high temperature oxidation resistance more than ASTM Gr.37 (Ti-1.5Al), which was the existing titanium alloy for exhaust systems. Specifically, high temperature oxidation resistances of Ti-Al-Si alloys and Ti-Al-Si-Nb alloys were evaluated from viewpoints of weight gain, formation of oxygen diffusion zone, thickness reduction, grain growth and embrittlement. It was found that small amount additions of Al, Si and Nb were effective in improvement of oxidation resistance of titanium. On the basis of this result, Ti-0.5Al-0.45Si-0.2Nb alloy was developed. This alloy has excellent oxidation resistance and suitable strength property for exhaust systems used at high temperature. This alloy is consequently considered to be applied to not only motorcycle exhaust systems but also automobile exhaust systems.
