**Zhimin Wang 1, Lulu Sun 2, Wenchao Ke 3, Zhi Zeng 3, Wei Yao <sup>2</sup> and Chunming Wang 4,\***


Received: 15 July 2020; Accepted: 20 August 2020; Published: 3 September 2020

**Abstract:** The joining of high-temperature titanium alloy is attracting much attention in aerospace applications. However, the defects are easily formed during laser welding of titanium alloys, which weakens the joint mechanical properties. In this work, laser oscillating welding was applied to join TC31 high-temperature titanium alloy. The weld appearance, microstructure and mechanical properties of the laser welds were investigated. The results show that sound joints were formed by using laser oscillating welding method, and a large amount of martensite was presented in the welds. High mechanical properties were achieved, which was approaching to (or even equaled) the strength of the base material. The joints exhibited a tensile strength of up to 1200 ± 10 MPa at room temperature and 638 ± 6 MPa at 923 K. Laser oscillating welding is beneficial to the repression of porosity for welding high-temperature titanium alloy.

**Keywords:** laser oscillating welding; high temperature titanium alloy; microstructure; mechanical properties
