Unravelling the abrasion resistance of two novel meta-stable titanium alloys on the basis of multi-pass-dual-indenter tests

Multi-pass-dual-indenter (MPDI) scratch tests with various loading conditions were performed on two newly developed titanium alloys (Ti–10V–1Fe–3Al and Ti–10V–2Cr–3Al) to investigate their abrasion resistance under repetitive local sliding contact. A technically pure titanium sample was used as the reference. Various microstructures were established by different heat treatments, such as to turn the β-phase into a stable phase or a meta-stable phase showing Stress Induced Martensite (SIM) formation. The influence of phase evolution on the scratch resistance and corresponding failure mechanisms was unravelled. It was found that the phase morphology and fraction have a significant impact on the scratch resistance and that effect is applied load dependent. The scratch behaviour is closely related to the work hardening ability of the material surface especially at high loading conditions, while the original surface hardness is more relevant at low loading conditions. The observations definitely prove that, not withstanding the modest hardness level, a microstructure showing a combination of metastable β (trigger the stress-induced martensitic transformation) and flake α (enhancing the initial surface hardness) is the best route to improve the scratch resistance for these two titanium alloys, in particular for high load conditions.