Microstructural evolution and crystal orientation of electromagnetically stirred al alloy in the semi-solid state

Abstract

Through more than three decades of development, a semi-solid metal processing has been successfully established as a unique casting technique to produce a structural component for an automobile industry with high integrity and improved mechanical properties. A slurry-on-demand process to make the semi-solid slurry having a fine and globular microstructure has been very important in the semi-solid metal process. In the present study, the orientation distribution functions (ODFs) calculated from the pole figure data were examined and tried to characterize the bulky morphology of primary solid phase of the semi-solid slurry of Al-Cu alloy produced with various magnetic flux density of 100 to 300Gauss in the specially designed electromagnetic (EM) stirrer. Columnar dendritic structure of primary a phase was turned into a rosette and globular structure by EM stirring during solidification. The primary a phase was refined and globularized with increasing a magnetic flux density of EM stirring. Also, due to the EM stirring the tendency to random orientation was appeared. In the case of unstirred Al-Cu alloy the < 110 >//ND texture was developed strongly and < 100 >//ND and < 111 >//ND texture was weakly developed. But with the increase of the EM stirring strength, < 100 >//ND and < 111 >//ND texture were more strongly advanced. Due to EM stirring the texture was almost completely randomized.