Effect of tungsten micro-scale dispersed particles on the microstructure and mechanical properties of Ti–6Al–4V alloy

Highlights: • The W addition can increase strength and ductility of Ti–6Al–4V alloy simultaneously. • Fine-grain strengthening is the dominant strengthening mechanism, which contributed 72% of the total strength increment, and the load transfer effect also contributes some of the total strength increment in this study. -- Abstract: Ti–6Al–4V (TC4) alloy and Ti–6Al–4V-5 wt.%W (TC4-5%W) alloy were fabricated by spark plasma sintering (SPS). The crystalline structure and microstructure of both TC4 alloy and TC4-5%W alloy were confirmed using X-ray diffraction (XRD) technique, scanning electron microscopy (SEM), and transmission electron microscopy (TEM), respectively. The XRD patterns suggested that a similar crystalline structure was formed in both of TC4 alloy with and without the W addition. SEM and TEM indicated that the dispersed W particles can refine the β grains, α colonies and coarsen the α laths by acting as the supernumerary nucleation sites for α laths during the β→α+β transformation process. Moreover, a comparative analysis of the mechanical properties of both TC4 and TC4-5%W alloys was obtained by the tensile tests, which is found that the W addition can increase the strength and ductility of TC4 alloy simultaneously. It is found that fine-grain strengthening is the dominant strengthening mechanism, which contributed 72% of the total strength increment. Meanwhile, the load-bearing effect also contributes to some of the total strength increments in this study. This study concluded that TC4 with W dispersed particles had a great potential to use as a novel Ti alloy with high strength and good ductility.