Effects of annealing on high velocity compaction behavior and mechanical properties of iron-base PM alloy

Abstract

High performance PM iron-base alloy was fabricated with annealed powder by high velocity compaction. The effects of powder annealing on densification behavior, variations of stress waves and the resulting mechanical properties of iron-base alloy were studied. The results show that micro-hardness of the powder decreases from 97 Hv to 81 Hv after annealing at 800 °C, facilitating the improvement of powder plasticity and compressibility. Compared with the compacts prepared from unannealed alloy powder, green density of the compacts made from annealed alloy powder is 0.11–0.25 g/cm3 higher at the impact velocity range of 6.2–9.4 m/s. Green density of the compact made from annealed alloy powder is as high as 7.61 g/cm3 at 9.4 m/s. The tensile strength, yield strength and hardness of the heat treated specimen reach 1459 MPa, 1185 MPa and 50.2 HRC, respectively.