Study on the Microstructure and Properties of TC4 Alloy Based on Water-Jet-Guided Laser Technology

Ti–6Al–4V (TC4) dual-phase titanium alloy is widely used in aerospace components owing to its excellent strength-to-weight ratio and high-temperature stability. However, conventional machining often generates a wide heat-affected zone (HAZ) and oxide or recast layers, which deteriorate the microstructure and reduce long-term reliability. In this study, the water-jet-guided laser (WJGL) process was applied to investigate how coupled laser–water interactions influence the groove morphology, elemental distribution, and crystallographic evolution of TC4 alloy. Under optimized parameters, the WJGL process reduced the HAZ width to less than 1 $\mathsf{\mu }$m, effectively removed the resolidified layer, and suppressed surface oxidation. SEM, EDS, and EBSD analyses confirmed that the $\alpha$ + $\beta$ dual-phase structure remained stable, with no significant phase transformation or grain coarsening. Compared with conventional laser cutting, WJGL achieved smoother surfaces, improved interfacial integrity, and reduced thermal damage. These findings highlight the potential of WJGL for precision machining of high-performance titanium alloys and provide theoretical and experimental support for enhancing the microstructural control and service reliability of aerospace TC4 components.