Rheoforging of Wrought Aluminum Alloys
Wrought aluminum alloys have wide variety applications in aerospace and automobile industries, due to their superior properties compared to casting aluminum alloys. Rheoforging is a modification of thixoforging, which starts directly from the liquid phase instead of reheating of a billet. In the present process, suitable semi-solid slurries of wrought aluminum alloys are prepared by the LSPSF (low superheat pouring with a shear field) rheocasting process within 25s. The effects of processing conditions on the degree of spherical grain refinement in 2024, 6082 and 7075 alloys are discussed. 2024 and 7075 alloys have been used in order to investigate rheoformability of high performance aluminum alloy. Experimental results show that rheoforging based on LSPSF process can produce relatively homogeneous microstructure throughout the cup-shaped component. However, high solid fraction of semi-solid slurry promotes metal flow and results in solid/liquid segregation. Subsequent optimized heat treatments raise significantly the mechanical properties. Future potentials and challenges to be solved are discussed.
G. Hirt, A. Rassili, A. Bührig-Polaczek
H. M. Guo and X. J. Yang, "Rheoforging of Wrought Aluminum Alloys", Solid State Phenomena, Vols. 141-143, pp. 271-276, 2008