Effects of sintering processes on composite tool steels containing self-synthesized TiC

Abstract

In present study, synthesized TiC was formed via mechanical alloying by planetary ball milling Ti and carbon black. Nano-size TiC powders in spherical shape were synthesized by milling for longer than 8 h at 400 rpm. Raman spectroscopy and TEM analyses both confirmed TiC formation. 0-44 vol% of these TiC and tool steel powders were then sintered by combining two powder metallurgy routes, vacuum sintering and hot isostatic pressing (HIP) without encapsulation. It was found that the nano-size TiC particles distributed uniformly among the tool steel powders. HIP had positive effects in both reducing internal voids and increasing flexural strengths of vacuum sintered composites. Nearly full sintering density was achieved without encapsulation. The amount of TiC added was up to 44 vol%, and the hardness of composite such formed reached as high as 71.6 HRc. © 2010 ISIJ.