In-Situ Reactions during Direct Laser Deposition of a Functionally Gradient Ti64-B Composite

The paper presents the results of experimental studies on the synthesis of a metal-matrix composite by direct laser deposition, including the assessment of optimum irradiation modes to make such a material free of defects (pores, cracks, etc.). It is shown that in-situ synthesis is provided by laser irradiation of a powder mixture composed of polycrystalline boron and titanium alloy Ti64 in a ratio of 1 : 9 wt %. According to X-ray diffraction analysis with synchrotron radiation, scanning electron microscopy, and nanoindentation, the deposited material contains second phases in the form of TiB and TiB 2 ceramics. According to mechanical tests, the elastic modulus and the hardness of the Ti64 metal matrix are E av = 159.7 GPa and H av = 7 GPa, and those of synthesized particles (whiskers) are E av = 321.6 GPa and H av = 19.7 GPa, respectively.