Development of the 90WC-8Ni-2Cr3C2 cemented carbide for engineering applications

Abstract

In this paper, the microstructure and mechanical properties of 90WC-8Ni 2Cr3C2 cemented carbide, developed by powder metallurgy, were investigated using optical and scanning electron microscopy, XRD, and hardness tester. The results showed that the addition of 2 wt% Cr3C2 in the WC-Ni alloy system, using conventional adding method, was not favorable to densification. The porosity was characterized by the presence relatively large elongated pores distributed in the microstructure. As a result, there were not significant improvement of the hardness and flexural strength of the WC-8Ni-2 Cr3C2 cemented carbide in comparison with WC-10Ni cemented carbides without Cr3C2 addition, obtained from the literature. Fracture toughness results showed that the cemented carbide WC-8Ni-2Cr3C2 presented higher fracture toughness than that of WC-Co, WC-Co-2Cr3C2, and WC-Ni alloys from literature, which may be mainly attributed to the effectiveness of Cr3C2 to inhibit the excessive grain growth of the WC particles, producing a more refined and tough microstructure. Thus, despite the porosity, the mechanical properties values obtained of the developed 90WC-8Ni-2Cr3C2 cemented carbide are adequate for several engineering applications, where is required a good balance between hardness, wear resistance, and toughness.