Effect of tungsten dissolution on the mechanical properties of Ti-W composites

Blends of 90 wt.% Ti and 10 wt.% W powders were consolidated by powder metallurgy, using an initial W powder size that was very fine (0.7 and 2 μm) or very coarse (<250 μm). Dissolution of W powders in the Ti matrix during consolidation was almost complete for the former blends (thus forming Ti-10W “alloys”) but very limited for the latter blend (thus forming a Ti-10W “composite”). The Ti-10W alloys exhibit much higher yield and tensile strengths than the Ti-10W composite, indicating that tungsten strengthens titanium more efficiently as a solute atom (solid-solution strengthening) than as a second phase (composite strengthening by load transfer). The Ti-10W alloys also exhibit much higher ductility than the Ti-10W composite, whose brittle W particles exhibit fracture or pull-out from the matrix.