Verification and Refinement of Local Difference in TC4 Hollow Blade Pressing with Low Melting Point Alloy Mandrel

To effectively form an aero-engine blades with the hollow structures for better homogeneous performances, the low melting point (LMP) alloy is proposed as a mandrel. However, local differences are still unavoidable. In this paper, therefore, the cold pressing of hollow TC4 blades filled with an LMP alloy mandrel is combined with the appropriate heat treatment process. Besides, the local differences in the surface position, stress, microstructure, grain size, boundary orientation angle, and recrystallization distribution are all verified in different areas of the formed blade through finite element simulations and experiments. Moreover, a series of heat treatments procedures with respect to temperature and holding time are performed on the blade. The results demonstrate that those local differences decrease significantly, accompanied by the formation of new fine equiaxed grains in the optimal heat treatment process. The combined applications of cold pressing with the aid of an LMP alloy mandrel and heat treatment process for forming the TC4 hollow blade with better homogeneous properties can also be used as a novel strategy for manufacturing other hollow products.