Nanoscale TiB precipitates in laser deposited Ti-matrix composites

Metal-matrix composites based on boride reinforcements in a titanium base matrix have been deposited in situ from a powder feedstock consisting of a blend of Ti-alloy and elemental boron powders using the laser engineered net-shaping (LENS™) process. These composites exhibit a homogeneous multi-scale microstructure consisting of micron to sub-micron as well as nanometer scale TiB precipitates in a metal matrix. While the coarser precipitates result from rapid solidification of the liquid, the nanometer-scale precipitates are likely to form from the solid-state decomposition of a boron supersaturated Ti-base matrix. Such nanometer-scale TiB precipitates can play a prominent role in determining the mechanical properties of these composites.