Microstructure transformations of laser-surface-melted near-alpha titanium alloy

Microstructural transformations of near-alpha titanium alloy under laser-surface -melted and post-heat treated conditions were systematically investigated. The results show that, after laser surface melting treatment, a melted zone and a heat-affected zone are formed in the titanium alloy. The melted zone consists of columnar grains, which are characterized by fine a″ phase, distributed dispersively in acicular martensite phase α′. Martensite transformation occurs at a lower temperature in post-heating process. The α phase in the laser-surface-melted zone is further refined during the recrystallization, and a fine dispersive α + β microstructure is formed when experienced post-heat treatment at an elevated temperature.