Effect of sintering process on the microstructures and properties of in situ TiB_2-TiC reinforced steel matrix composites produced by spark plasma sintering

摘要

Spark plasma sintering (SPS) is a new technique to rapidly produce metal matrix composites (MMCs), but there is little work on the production of TiB_2-TiC reinforced steel matrix composites by SPS. In this work, in situ TiB_2-TiC particulates reinforced steel matrix composites have been successfully produced using cheap ferrotitanium and boron carbide powders by SPS technique. The effect of sintering process on the densification, hardness and phase evolution of the composite is investigated. The results show that when the composite is sintered at 1050℃ for 5 min, the maximum densification and hardness are 99.2% and 83.8 HRA, respectively. The phase evolution of the composite during sintering indicates that the in situ TiB_2-TiC reinforcements are formed by a hybrid formation mechanism containing solid-solid diffusion reaction and solid-liquid solution-precipitation reaction. The microstructure investigation reveals that fine TiB_2-TiC particulates with a size of ~2μm are homogeneously distributed in the steel matrix. The TiB_2-TiC/Fe composites possess excellent wear resistance under the condition of dry sliding with heavy loads.