Effect of Si and Ge Addition on the Evolution of Microstructure in Near Alpha Titanium Alloy

Abstract

Near α titanium alloys have found wide application as compressor blades, fins in aero engines [1]. In order to achieve better fuel economy, there is a major focus to increase the operating temperature of these components. Addition of small amount of silicon has been found to significantly improve creep resistance [2-7]. Highly stable grain boundary precipitates could reduce the grain boundary sliding and uniform precipitation could restrict the dislocation creep at high temperature. Applications of Si added titanium alloys are limited up to 600oC. Ge being analogous to Si shows better solid solubility, particularly at room temperature [8]. Consequently, it can lead to solid solution strengthening. It has also been reported that germanides have better thermal stability compared to silicides [8]. However, there is no investigation available on the effect of Ge on the microstructural evolution in near α titanium alloys. Therefore, the present study aims at understanding the effect of Si and Ge addition on the evolution of microstructure in near α titanium alloys.