High-performance, low-cost titanium metal matrix composites

摘要

Titanium-based discontinuously reinforced metal matrix composites were obtained by mechanical alloying and spark plasma sintering. Titanium sponge was used as a raw material to minimize costs, and a small amount of calcium was added as a process control agent. α and β Titanium matrices were obtained by the use of two different compositions, and 3 wt% carbon black was used as the carbide former. The milled powder was then sintered at low temperature and low pressure. An in-situ precipitation occurred involving a fine and well dispersed distribution of titanium carbide in a titanium matrix. Depending on the starting composition, the volumetric quantity of titanium carbide was between 23 and 31 vol%. Despite the high ceramic loading, all of the samples could withstand tensile loading with distinct plastic deformation. The best samples showed a yield stress of 1013 MPa, Young's modulus of 137 GPa, an ultimate tensile stress of 1181 MPa and a strain at fracture of 5%. These results were obtained without any other additional heat treatment or hot deformation step.