δ Phase precipitation in cast alloy IN625 with different Cr content and associated mechanical properties

Abstract

The cast alloy IN625 has been developed recently and evaluated as a candidate material for the 700 °C class A-USC plants. In order to clarify the effects of Cr on δ phase precipitation and the mechanical properties in cast alloy IN625, the aging treatment experiments on cast alloy IN625 with different Cr additions were carried. It was revealed that the precipitation of δ phase in cast alloy IN625 after aging at 750 °C was nearly unaffected by Cr content. The tensile properties of cast alloy IN625 appeared to be insensitive to Cr content, but sensitive to δ phase. Stress rupture tests showed that, the rupture time of aged alloys increased when compared to the solid solution alloys. Besides, when the fraction of δ phase increased from 18% to 35%, different trends emerged in the stress rupture life at 400 MPa and 375 MPa, respectively.