Effect of laser energy density on the microstructure and performance of homogeneous-material laser cladding repair layers for TA15 titanium alloy

Abstract

This study employs homogeneous material laser cladding to fabricate a metallurgically bonded repair layer compositionally identical to the TA15 substrate. The microstructure and phase composition were characterized using XRD, SEM, EBSD, and XPS, while electrochemical and wear tests were performed to evaluate performance. The results show that ultrafast solidification produces a fine acicular microstructure with refined grains and reduced BCC phase content. At the optimal energy density (S2, 31.3 J/mm³), the repair layer exhibits a microhardness of 455 ± 6 HV, representing a 41% increase over the substrate, and achieves a wear rate as low as 2.61 × 10⁻⁴ mm³/N·m. XPS analysis confirms that grain refinement promotes the formation of a dense TiO₂-based oxide film, which effectively suppresses Cl⁻ ion penetration, leading to a low corrosion current density of 1.81 ± 0.06 × 10⁻² μA/cm². These findings demonstrate that compositionally matched laser cladding not only enhances wear and corrosion resistance but also provides a reliable strategy for additive remanufacturing of critical titanium alloy components.