Study on Mechanical Alloying of TiB_2 Particulate Reinforced Titanium Matrix Composites

摘要

TiB_2 particulate reinforced titanium matrix composites were prepared by mechanical alloying and spark plasma sintering. Volume fraction of TiB_2 powders in the composites are 5%, 10%, 15%. The effect of milling time and the volume fraction of reinforcement on microstructure and properties of the composites were studied. The results show that with increasing milling time, the size of powder particles decreases, quantity of them increases, and microstructure of the sintered samples becomes finer and more uniform. When milling time reaches 30h, the trend of powder agglomeration increases, the downward trend of the particle size becomes slowly. With the milling time, the density of titanium matrix composites is on the rise. The density of 10vol%TiB_2 particulate reinforced titanium matrix composites can reach 4.799 g/cm~3, with 30h milling time and sintering at 900°C. The density and hardness of the composites increase with increasing the volume fraction of TiB_2. When the volume fraction of TiB_2 is 15%, after milling 10h and sintered at 800°C, the density and hardness of the composites can reach 4.713g/cm~3 and HV851.58.