Effects of Zirconium Addition on Microstructures and Mechanical Properties of Co-29Cr-6Mo Alloy

Abstract

Co-29Cr-6Mo alloys consisting of 0∼1.76% Zr were prepared and heat-treated at 1210°C for 2 h or 1230°C for 3 h. Three types of precipitates were identified. With more than 0.37% Zr content, precipitates are mixtures of σ phase and (Zr, Mo)-rich phase. The σ phase dissolves into a matrix and the (Zr, Mo)-rich phases change its composition into a Zr-rich phase with heat treatment. An alloy with a solid solution containing 0.01% Zr exhibits improved mechanical properties.