Abstract
The addition of small amount of boron to Ti and it alloys refines the as-cast microstructure and enhances the mechanical properties. In this paper, we employ nanoindentation on each of the constituent phases in the microstructure and ‘rule-of-mixture’ type analysis to examine their relative contributions to the strength enhancement in a Ti–6Al–4V alloy modified with 0.3wt% B. Our results indicate to two main contributors to the relatively higher flow strength of B-modified alloy vis-á-vis the base alloy: (a) strengthening of alpha phase due to the reduction in the effective slip length that occurs as a result of the microstructural refinement that occurs upon B addition, and (b) composite strengthening caused by the TiB whiskers present in the alloy.