Microstructure and mechanical properties of high carbon M2 powder metallurgy high-speed steel prepared by the carbide addition

ABSTRACT This paper used carbonyl iron powder and carbide powder as raw materials to prepare high carbon M2 powder metallurgy high-speed steel through the cold compaction-sintering method. The evolution of microstructure and properties of the material at different sintering temperatures were emphatically studied. The results show that: The microstructure of the samples is that different types of carbides are uniformly dispersed in the matrix. Since the dissolution of the original carbides is a continuous process, the precipitated carbides are constantly changing with the increase of sintering temperature. Moreover, M2 steel achieves sintering densification near the solidus temperature, the sintering window is expanded to 10–15°C. In the sintering temperature range, the carbides in the samples are fine and uniformly dispersed. The material sintered at 1225°C has the best mechanical properties, with a bending strength of 2754 MPa, and a hardness of 51 HRC. In addition, mechanical properties are greatly improved by heat treatment.