Effect of TiB2 addition on the mechanical and biological response of spark plasma sintered Ti6Al7Nb matrix composites

Abstract

In situ fabrication of TiB whiskers (TiBw) reinforced Ti-matrix composites (TMCs) was carried out with the addition of TiB2 particles in Ti6Al7Nb matrix using low energy ball milling and subsequent consolidation via Spark Plasma Sintering (SPS). The ball mixing of 0.5 %, 1.5 %, and 3 % TiB2 resulted in its distribution ratio (RD) of 1.05, 3.2, and 6.5, respectively. The in situ TiBw formations as a reaction between the Ti6Al7Nb matrix and TiB2 particles resulted during sintering. This TiBw inclusion in different regions caused the retardation of grains from growing and resulted in grain refinement. The presence of a stiff TiBw phase in combination with grain refinement was ascribed to the increased hardness and higher strength in the fabricated composites. Maximum hardness (~ 496 Hv) and strength (~ 2233 MPa) was achieved in the 3 % TiB2 containing composites among all. The biological response showed better cell adhesion and proliferation without any toxic effect on all fabricated samples when compared to the wrought Ti6Al7Nb. The enhanced cell proliferation on the TiBw composites than the pure alloy demonstrates them as promising materials for biomedical applications.