Microstructural characterization and failure mechanism of vacuum plasma sprayed Ti-6Al-4V/B4C composite

In the current study, metal-matrix composite of Ti-6Al-4V alloy reinforced by B4C was produced by vacuum plasma spray (VPS) processing. Microstructural analyses were made by optical microscopy, scanning and transmission electron microscopy (SEM and TEM), and X-ray diffraction (XRD). Mechanical properties of the composite were examined using three-point bending test and Vickers microhardness. Room temperature mechanical properties of the as-sprayed Ti-6Al-4V alloy and composite showed an increase in the microhardness and flexural modulus and a decrease in the flexural strength. Failure of the composites occurred along reinforcement-matrix interfaces due to the presence of a high density of microcracks, pores, and weak interfaces between splats. Moreover, erosive mechanism behavior of the composite was studied and it was seen that both plastic deformation of the alloy and brittle fracture of B4C phase had caused erosive wear in the composite. (C) 2014 Elsevier Ltd. All rights reserved.