Effects of warm die on high velocity compaction behaviour and mechanical properties of iron based PM alloy

Abstract

An iron based alloy powder (Fe–2.0Ni–1.0Cu–0.8Cr–0.5C) was used as raw material to prepare high density iron based alloy by warm die high velocity compaction (WHVC). The effects of warm die on high velocity compaction (HVC) densification behaviour, variations of stress waves and the resulting mechanical properties of iron based alloy were studied. The results show that, under the warm die condition at 100°C, the HVC behaviour of powder changes and the green density improves. Compared with the compacts prepared by HVC, the green density of compacts prepared by WHVC is 0.09–0.27 g cm^− 3 higher at the impact velocity range of 6.2–8.7 m s^− 1. The green density of compacts prepared by WHVC reaches 7.62 g cm^− 3 at 7.9 m s^− 1. The compacts were sintered at 1150°C in H₂ atmosphere. The tensile strength, yield strength and hardness of the heat treated samples reach 1571 MPa, 1360 MPa and 51.2 HRC respectively.

Keywords:

• High velocity compaction
• Iron based alloy
• Warm die
• Stress waves
• Mechanical properties

Acknowledgements

This work is financially supported by the National High Technology Research and Development Program of China (863 Program) (2013AA031101) and the National Nature Science Foundation of China (51374027).