Nano-TiB whiskers reinforced Ti–6Al–4 V matrix composite fabricated by direct laser deposition: Microstructure and mechanical properties

Abstract

Titanium matrix composites (TMCs) have attracted widespread research interest due to their excellent properties. Herein, TMC reinforced with quasi-continuous reticular nano-TiB whiskers (nano-TiBw) was fabricated via a direct laser deposition method. The network of TiB reinforcements was found to be equiaxial and dendritic, and the addition of boron was shown to be beneficial to the equiaxial transition and refinement of α grains. The interface between the nano-TiBw and Ti64 matrix was observed to be clean and flat. The microhardness of the TMC was 465.1 HV0.025, 31% higher than that of the Ti64 alloy. Compressive tests showed that the TMC exhibited high ultimate compressive strength and good plasticity due to the grain refinement of the matrix and load transfer effect of nano-TiBw. The lower friction coefficients, smaller wear tracks, and minor wear weight loss revealed the superior wear resistance of the TMC in comparison to that of the Ti64 alloy. The reticular TiBw was found to be responsible for reducing the sensitivity of the TMC to adhesive wear.