Enhancing the surface integrity and wear resistance of selective Laser melted Ti-6Al-4 V via ultrasonic shot peening: A parametric study

In this study, the effects of ultrasonic shot peening (USP) on the surface properties and mechanical performance of Ti-6Al-4 V samples fabricated by selective laser melting (SLM) were systematically investigated. The samples were treated with SiC and WC shot media, varying in diameters of 2, 3, and 4 mm, and treatment durations of 3, 6, and 9 min. The results demonstrated significant changes in the surface residual stresses, shifting from tensile to compressive. For the untreated samples, the residual stress was 217 MPa, which increased to 390 MPa and 370 MPa for SiC and WC shots with 2 mm diameter after 9 min of treatment, respectively. For the 4 mm diameter shots, the residual stresses increased to 530 MPa for SiC and 488 MPa for WC. Surface hardness reached a maximum of 514 HV under SiC treatment with 4 mm diameter shots and 9 min of processing time. Surface roughness significantly decreased from 11.8 µm to 2.12 µm, with the minimum Ra achieved using WC shots (2 mm diameter, 9 min). Additionally, wear performance showed a remarkable improvement, with mass loss reduction up to 89% compared to untreated samples. These findings indicate that USP is an effective method for enhancing surface properties, wear resistance, and durability of Ti-6Al-4 V components in industrial applications.