Effects of Microstructural Evolution and Mechanical Properties on 440C-TiC Composite Steel by HIP Treatment

The aim of this paper is to investigate the effects of HIP treatment on 440C-TiC composite steel. In this study, AISI 440C stainless steel powders were added with different amounts of TiC powders (25, 33 and 40 wt%), the composite materials were sintered at 1473 K, 1573 K, and 1673 K, followed by different pressures of HIP and HIP plus heat treatment. HIP treatments were used 120 and 150 MPa at 1523 K 1 hour. Experimental results showed that the microstructure of matrix had small needle structures after HIP treatment, which were effective in improving the hardness and strength. Furthermore 440C-TiC composite steels which were added with 25wt% TiC powder after 1673 K sintered and high pressure HIP treatments, TiC powders were uniformly dispersed in the high chromium stainless steel matrix were observed and consequently possessed the higher hardness (HRA 85) and highest TRS (1213 MPa).