Microstructural Characterization and Properties of Microalloyed Powder Metallurgy Steels

Abstract

The aim of this research is to investigate the effect of alloying elements of nickel, molybdenum, carbon and copper on hardness, density and microstructure of low alloy steel produced by powder metallurgy method. The results showed that molybdenum addition could lead to increase the density and hardness. Also, an increase in carbon content up to 1 wt. % could result in an increase in density and hardness. Copper is mainly added to increase strength as a result of solid solution hardening effect. Molybdenum is a ferrite stabilizer while Nickel is a strong austenite stabilizer. Consequently, the nickel and copper rich regions are mainly surrounded by austenite or bainite. Regions with higher amounts of alloying elements appeared to be martensitic islands. Increasing martensite and bainite volume fraction led to increase hardness.