Effect of FSW process on anisotropic of titanium alloy T-joint

ABSTRACT

A T-joint with two welds in the same welding direction was successfully connected for an α titanium alloy using friction stir welding (FSW). The texture and joint properties under different stress directions were analyzed. Results show that grains undergo obvious recrystallization in stir zone (SZ), and the grain of SZ in the first weld is coarser compared to the SZ in the second weld due to secondary welding heat cycle. The welding temperature exceeding or not exceeding β transus greatly affects the final microstructure of the SZ, but does not affect its texture type. The Schmid factors are higher in rolling direction than those in normal direction, so the base material and SZ are more likely to deform when stress is applied in the rolling direction, which results in a lower microhardness in this direction. In addition, the effect of anisotropy on mechanical property was weaker in SZ than in base material.

KEYWORDS:

• T-joint
• FSW
• texture
• microstructure
• recrystallization
• temperature
• transus
• microhardness
• stress
• anisotropy

Acknowledgments

The authors are grateful for the support provided by the fund of the State Key Laboratory of Solidification Processing at NPU in China (2019-QZ-01).

Disclosure

There are no competing financial interests.

Additional information

Funding

This work was supported by the State Key Laboratory of Solidification Processing at NPU in China [2019-QZ-01].