Microstructure, Mechanical Properties and Wear Performance of WC/Brass Composites Produced by Pressureless and Spark Plasma Sintering Processes

Abstract

Tungsten carbide reinforced brass matrix composites with 30 and 70 wt% brass were synthesized by mechanical milling and densification of brass/tungsten carbide powder mixtures. Two different sintering methods included pressureless and spark plasma sintering were applied for densification of the milled powders. The relative density of the spark plasma sintered samples was much higher than those of the pressureless sintered ones confirming higher microstructural densification during spark plasma sintering. The hardness of the spark plasma sintered composites containing 30 and 70 wt% brass were 303 and 175 Vickers, respectively which was about five times more than those of the pressureless sintered composites with similar weight percent of brass. In addition, the wear performance of the composites was investigated by the pin on disc method. The spark plasma sintered samples with 30 wt% brass showed the highest wear resistant among the processed samples owing to their higher hardness. The microscopic observations revealed that delamination and adhesion were the dominant wear mechanisms for the pressureless and spark plasma sintered composites, respectively. The bending strength of the spark plasma sintered samples with 30 and 70 wt% brass were 329 and 453 MPa, respectively.