Effects of geometrical size and structural feature on the shape-distortion behavior of hollow Ti-alloy blade fabricated by additive manufacturing process
Shuang Gao, Zhijun Tan, Liang Lan, Bo He
Abstract
In the additive manufacturing (AM) process, metal powder can be directly used to produce metal components. Unfortunately, a large thermal gradient is developed during the AM process, which leads to the generation of residual stress and complex shape-distortions. In this study, the influence of the geometrical size and structural features of a hollow Ti-alloy blade prepared by the AM process on the shape-distortion behavior was systematically investigated using the three-dimensional (3D) blue-light scanning technology. The results indicated that the concentrated residual stress was developed on the surface of the blade. The compressive residual stress induced a bulging distortion, while the tensile residual stress resulted in denting distortion on the blade surfaces. When the blade height and torsion angle increased, the shape-distortion was aggravated owing to the accumulation of microscopic strain and the elevated temperature gradient. However, the shape-distortion mitigated when the wall thickness significantly increased or the stiffened plates were set within the blade cavities, owing to a strengthening structural constraint which inhibited the distortion behavior. In addition, a control method for the shape-distortion during AM process was able to implement based on the proper optimization of the geometrical sizes and structural features of complex 3D-printed components.