Comparison of Microstructural Changes in a SIMA Processed A356 Aluminum Alloy after Unidirectional Compression and Rolling: Effect of Pressure Depth
In this study, in order to compare effect of unidirectional compression and rolling on final microstructure of strain induced melt activated (SIMA) A356 aluminum alloy, rectangular samples with dimensions of 3cm×5cm in area and 1cm in thickness and cylindrical specimens with 2.5cm in diameter and 1cm in length, have been prepared for rolling and compressing processes, respectively. Then, these samples were plastically deformed at a same strain in ambient temperature. Afterward, the strained samples were cut into equal quarters. In the next stage, to produce globular microstructure, these specimens were partially remelted in 580°C for different times. Results obtained from light microscopy showed that specimen's thickness and so, its strain affected zones influence on the globulization of dendrites. In addition, it was seen that at a given strain and constant diameter, increase of H/D ratio led to increase of needed time for reaching a certain sphericity in cylindrical samples. Also, it was showed that microstructural evolutions during SIMA processing of both rolled and unidirectional compressed samples were relatively identical. However, at a same condition, ultimate size of globulized dendrites in the rolled samples was smaller than those of compressed ones.
G. Hirt, A. Rassili, A. Bührig-Polaczek
M. Hajian Heidary et al., "Comparison of Microstructural Changes in a SIMA Processed A356 Aluminum Alloy after Unidirectional Compression and Rolling: Effect of Pressure Depth", Solid State Phenomena, Vols. 141-143, pp. 391-396, 2008