Comparative Study on Wear Properties of TC4 Alloy by Laser Selective Melting and Traditional Forging Process at Different Temperatures

This study investigated the dry friction and wear behavior of TC4 titanium alloys fabricated by selective laser melting (SLM) with different orientations (0°, 45°, and 90°) at elevated (200 °C) and ambient (25 °C) temperatures. Ball-on-flat reciprocating friction and wear tests were performed using an HSR-2M wear tester to evaluate the wear performance of both 800 °C-annealed SLM-fabricated TC4 alloys and traditional forged TC4 alloys under varying temperature conditions. The microstructure, wear morphology and wear volume were characterized using optical microscopy, scanning electron microscopy (SEM) and laser confocal microscopy. The results demonstrated that SLM-fabricated TC4 alloys exhibited superior wear performance compared to forged TC4 alloys at both 25 and 200 °C. This enhancement was attributed to the fine, acicular martensitic α phase of the SLM alloys, which possessed superior hardness and tensile strength when compared to the equiaxed α phase of the forged alloys. After annealing at 800 °C for 6 h, the wear performance differences among the SLM alloys with different orientations were negligible, as the microstructures and hardness of the alloys became comparable. At room temperature, abrasive wear was the dominant wear mechanism for both SLM and forged TC4 alloys, whereas oxidative wear became predominant at 200 °C. High-temperature third-body layer, such as TiO₂ and Fe₂O₃ formed during the tests acted as a protective layer, resulting in a reduction of wear volume by approximately 20%. The 800 °C-annealed SLM TC4 alloys exhibited excellent wear and mechanical properties, suggesting their promising potential for high-performance engineering applications.