Microstructure and Mechanical Properties of Ti-48Al-2Nb-2Cr Matrix High Temperature Self-Lubricating Composites by Addition of 38%CaF2-62%BaF2 Eutectic Solid Lubricants

摘要

Tribological properties and mechanical strengths of high temperature self-lubrication composites must be considered fully. Sometimes addition of solid lubricants result in the mechanical properties degradation of the composites at room temperature. In this article, the microstructure and mechanical properties of Ti-48Al-2Nb-2Cr composites with addition of different weight contents of 38%CaF2-62%BaF2 eutectic solid lubricant were evaluated. It is indicated that pores or cavities are mostly concentrated in solid lubricant and in chromium, niobium aluminide. The bending strength and fracture toughness of Ti-48Al-2Nb-2Cr composites with 0-5 wt% solid lubricant were enhanced significantly. The strengthening mechanism is due to solid solution hardening and increase of dislocation motion. However, when additions of lubricant content exceed 5wt%, increase of porosity and cracks result in the decreases of mechanical properties.