Microstructure and Mechanical Properties of Laser Deposition Repaired TA15 Titanium Alloy

Abstract

The technology of laser deposition repair was used to repair two kinds of mis-machining defects in TA15 titanium alloy forgings. The effect of solution-aging treatment on microstructure and tensile properties of TA15 titanium alloy at room temperature was investigated. The results show that the entire heat affected zone of annealing state presents a continuous microstructural transition from bimodal structure to basket weave characterized by coarse columnar β with fine α/β lamellar structure. After solution-aging treatment, martensitic transformation occurs in β phase, the primary α phase and hexagonal martensite α' are obtained, a part of continuous prior α boundary is broken, becomes spheroidized and illegible, and α laths grow up to bunch on some broken boundary. The strength of annealing sample is higher than that of forging, but the plasticity is lower. The tensile properties of groove repair sample and body repair sample after solution-aging are obviously improved compared with the annealing.

Keywords

• laser deposition repair
• titanium alloy
• heat treatment
• microstructure
• mechanical property