Microstructure and mechanical properties of fine-grained TiB2/AZ31 composites prepared via powder metallurgy

摘要

In this work, the fine-grained TiB2/AZ31 composites with different TiB2 additions were successfully fabricated via powder metallurgy, which exhibited the simultaneous improvement of strength and ductility. The average grain size of these TiB2/AZ31 composites could reach below 2.5 mu m, which also achieved the low porosity and high hardness. Tensile test results indicated that AZ31-5wtTiB2 composites exhibited the best comprehensive mechanical properties at room and elevated temperatures. The yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) of AZ31-5wtTiB2 could reach 219 MPa, 312 MPa, and 15.5 at room temperature, while the YS, UTS, and EL at 300 degrees C increased by 18.0, 19.5, and 156.4 compared with AZ31. The grain refinement played a dominant role in simultaneous improvement of strength and ductility. Besides that, the fracture mechanism of the AZ31-5wtTiB2 composites at both room temperature and elevated temperature showed ductile fracture.