Effect of Forging Process on Microstructure of TiB_w Reinforced Nearα High-Temperature Titanium Matrix Composite

Near α high-temperature titanium matrix containing 3vol% TiB_w reinforcement was treated by single pass unidirectional forging with different strain rates (0.01-0.10 s^-1) and deformation amount (30%-70%) and multi-directional forging. Then the influence of forging process on the microstructure of the composite was studied. The results show that after unidirectional forging with different strain rates, TiB_w reinforament in composite distributed evenly perpendicular to the forging direction; the fragmentation degree of TiB_w reinforcement increased with increasing strain rate; the content of equiaxed α phase decreased, and the content of lamellar α phase and β transition structure increased. After multi-directional forging, the fragmentation of TiB_w reinforcement increased, and the directional alignment tendency was more obvious with increasing deformation amount; the content of equiaxed α phase increased, and the content of lamellar α phase and β transformed structure decreased. The TiB_w reinforcement in the matrix was broken after multi-directional forging, but the distribution had no obvious orientation; the matrix structure consisted of lamellar α phase and β transition structure; the yield strength and compressive strength of multi-directional as-forged composite were 1 512, 1 802 MPa, which were 15.4% and 5.9% higher than those of as-cast composite.