Effect of Al-Nb Content on Microstructure and Properties of GH706 Alloy for Rotor

The effects of increasing Al content and decreasing Nb content on microstructure and mechanical properties of GH706 alloy before and after long time age heat treat were studied. The results show that increasing Al content and decreasing Nb content in alloy contribute to the disappearing of gamma ", eta, Laves and delta phases in alloy. After aged at 750 degrees C for 500 h, gamma' and eta grow up slightly and the mechanical properties have a limited reducing. While the precipitates of alloy without modification (conventional GH706) grow up rapidly and the mechanical properties decrease obviously. The alloy can be used at higher temperatures with modification of increasing Al content and decreasing Nb content.