Processing, microstructure and properties of 316L stainless steel-tungsten carbide composites

Abstract

Tungsten carbide (WC) particles were added into 316L stainless steel matrix composites and were fabricated by conventional powder metallurgy route. The amount of WC powders was varied from 5 wt% to 15 wt%. The influence of processing parameters, i.e. tungsten carbide content, sintering temperature and holding time on microstructure and properties of the composites were investigated. The composite specimens were subjected to sintering at the temperature range of 1200 - 1300 °C in H ₂ atmosphere, using holding time between 30 - 60 minutes. The microstructure investigation was systematically carried out. The surfaces of specimens were successfully exposed after various sample preparation procedures. When using the etchants of glycerol, hydrochloric acid and nitric acid in the ratio of 3: 3: 1 etching for 7 minutes showed more effective reveal of the microstructure of the specimens. An addition of WC into the specimens generally increases the hardness of the specimens at all sintering temperatures and times. It was found that the shrinkage increased and the porosity decreased when the sintering temperatures were increased.