Slurry Erosion Wear Resistance and Impact-Induced Phase Transformation of Titanium Alloys

Abstract

Erosion wear resistance and impact-induced phase transformation of titanium alloys TA2 (pure Ti), TC4 (Ti–6Al–4V) and TC11 (Ti–6.5Al–3.5Mo–1.5Zr–0.3Si) were investigated using a slurry jet tester. The slurry erosion wear resistance of TA2 is comparable to that of 304 stainless steel, especially at the impingement angle 90°. Although TC4 and TC11 have higher hardness, TA2 possesses the best erosion wear resistance except TC11 at 15°. With the increasing erosion time, the eroded surface hardness of TC11 at the impingement angle 90° increases and then decreases, while the volume loss rate drops in the first 15 min, then increases until 30 min, and then slightly decreases again. With XRD characterization and SEM observation, erosion-induced phase transformation from metastable β-phase to α-phase is proved on the surface of titanium alloy TC11. And the thickness of visible phase transformation layer is about 10 μm. Phase transformation influences the erosive wear mechanism of titanium alloys. At the impingement angle of 30°, the material removal of TC4 and TC11 can be described as micro-plowing and lip extruding, while plowing mark is not a typical surface morphology of TA2, indicating a better work-harden ability. So, stabilizing β-phase can be an effective way to improve the erosion wear resistance of titanium alloys.