Abstract:
Ti6Al4V/B
4C titanium matrix composites with different B
4C contents were prepared by vacuum arc melting. The microstructure and mechanical properties were characterized and analyzed by optical microscope, scanning electron microscope, microhardness tester, static compression and tensile test. The results show that in the process of arc melting, B
4C reacts with titanium matrix in situ to form TiB, TIC and TiB
2 phases. TiB presents one-dimensional long whisker shape, TiC presents granular shape, and massive TiB
2 is formed when the content of B
4C is 10 wt.%, and a special hollow prismatic Ti (B
xC
y) polymer may be formed. TiB
2 produced by in-situ reaction significantly improve the microhardness of titanium matrix composites. When the content of B
4C is 0.5 wt.%, the continuous network and evenly distributed structure of TiB and TiC produced by the in-situ reaction of titanium matrix composites has the best mechanical properties. The maximum compressive strength of the sample reaches 1 990 MPa and the maximum compressive strain is 35.5%. The compressive property exceeds that of molten titanium alloy. The tensile strength reaches 1 034 MPa, which is nearly 24% higher than that of molten titanium alloy, but the plasticity decreases. With the increase of B
4C content, the tensile strength decreases gradually, titanium matrix composites gradually change from ductile fracture to brittle fracture.