Direct energy deposition of SiC reinforced Ti-6Al-4V metal matrix composites: Structure and mechanical properties

The creation of metal matrix composites (MMCs) is an important strategy for obtaining heat-resistant products. Metal matrix composites provide superior characteristics of improved mechanical, high-temperature and tribo-logical properties. Manufacturing of MMCs by the methods of additive technologies contributes to the devel-opment of technical industries. In this paper, the formation of the structure, phase composition and mechanical properties of Ti-6Al-4V/SiC MMCs got by direct energy deposition were investigated. The compositions with 1 vol%, 3 vol%, 5 vol%, 7 vol% SiC are considered. The structure consists of SiC particles surrounded by a matrix of titanium martensite. However, during deposition, the matrix interacts with SiC particles to form TiC and Ti5Si3. Increasing the amount of ceramic content leads to a reduction of grains, which is associated with the formation of TiC at the grain boundaries. As the SiC content increases, the hardness increases because of an increase in the solid phases TiC and Ti5Si3, but these phases weaken the DED samples. The addition of 1 vol% SiC significantly increases the strength of the titanium alloy up to 1300 MPa with a relative elongation of 2.1%.