Effect of Annealing Temperature on Microstructure and Dry‐Sliding Behavior of Powder Bed Fusion–Laser Beam Ti-6Al-2Sn-4Zr-6Mo Alloy

Titanium alloys produced via powder bed fusion–laser beam exhibit a wide range of applications for high-performance components, due to their excellent strength-to-weight ratio. However, their poor wear resistance remains a significant limitation. Heat treatment offers a viable approach for enhancing the tribological performance of these alloys by modifying their microstructure. This study examines the influence of annealing temperature on the tribological behavior of the α–β titanium alloy Ti─6Al─2Sn─4Zr─6Mo during sliding against a quenched and tempered AISI 52100 in a block-on-ring configuration. The predominant wear mechanism identified in all samples is oxidative, while severe adhesion zones are observed in the as-built alloy. Annealing belowthe β-transus temperature (HT875) yields the largest enhancement in wear resistance, reducing the wear volume by 59%. This superior performance is attributed to the high ductility imparted by the microstructural coarsening, which allowed for the generation of a compact and functional mechanically mixed layer (MML), and to the high tendency for strain hardening, induced by tribological interactions, which guarantees enhanced load-bearing capacity. Conversely, despite being 14% harder than the HT875 condition, the HT600 condition demonstrates a 56% higher wear volume, which is attributed to the instability of the MML formed during sliding.