Research on Microstructure and High-Temperature Performance of Novel Ti65 Titanium Alloy with V-Groove Connection in Laser Additive Manufacturing

Abstract

Ti65 is a novel high-temperature titanium alloy tailored for use in the 650 °C temperature range. Its processing difficulties present substantial challenges to conventional manufacturing methods, compelling an exploration of alternative techniques. This study adopts laser additive manufacturing to join V-grooved Ti65 alloy specimens, thoroughly examining their microstructure and mechanical aptitude. Ultrasonic testing underscores the 90 ° V-groove’s integrity, showing no signs of porosity or unfused anomalies. Microstructural analysis reveals a distinct α lamellar configuration throughout the junction region, interface, and base matrix, accompanied by the emergence of Ti₃Sn and Si₃Ti₂Zr₃ silicide phases. Tensile assays conducted at room temperature suggest the V-groove connections outperform the additive-manufactured Ti65 alloy in strength. Contrarily, at elevated temperatures of 650 °C, the tensile strength surpasses that in the vertical orientation yet falls short of the horizontal, with notable declines in both fracture elongation and sectional contraction relative to the additive counterparts. Although there is a decrement in endurance strength, the material shows a promising creep resistance.