Microstructure of Discontinuously B₄C Reinforced Ti Metal Matrix Composites Processed by Hot-Pressing

Titanium matrix composites (TMCs) reinforced with ceramic particles are of major interest for applications that require materials combining high specific modulus and strength as well as superior corrosion behavior and wear resistance. The use of B4C particles as reinforcement presents several advantages in comparison to other ceramic materials, such as SiC or Al2O3. In fact, B4C is well recognized for its hardness and abrasion resistance, since it outperforms most technical materials. Furthermore, the lower density of B4C is of fundamental importance in applications where weight reduction is a key requirement concerning materials selection [1–3]. Reinforcement particles and matrix should be chemically bonded and not just mechanically interlocked, to enable adequate performance of discontinuously reinforced metal matrix composites (DRMMCs). Chemical bonding is promoted by the formation of a reaction zone that surrounds the reinforcement particles and results from their chemical reaction with the matrix in the course of the processing thermal cycle. The nature of the phases formed at the reaction zone as well as its extension and morphology are highly dependent of the processing conditions and should be carefully controlled in order to enhance the performance of DRMMCs. The present study is centered on the influence of the processing variables on the microstructural features of a TMC, reinforced with B4C particles, produced by hot-pressing.