Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Microstructural evolution of an A356 aluminum alloy processed by accumulative back extrusion N. Haghdadi1,2, A. Zarei-Hanzaki2, P.D. Hodgson1 for Frontier Materials, Deakin University, Waurn Ponds, VIC 3216, Australia 2School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, 11365-4563 Tehran, Iran 1Institute Abstract A356 aluminum alloy is one of the most common cast aluminum alloys, the microstructure of which consists of an aluminum matrix and eutectic silicon particles. Coarse and long Si particles are the main reason for the limited mechanical properties of this alloy. In order to spheroidize and refine the silicon particles, accumulative back extrusion (ABE) process was applied on a thixocast A356 aluminum alloy in the current study. The results indicate that the eutectic Si platelets are fragmented and spheroidized as a result of applying severe deformation at high temperatures. Mechanical fragmentation and thermal disintegration play a prominent role in Si particle break up. The average particle size decreased with decreasing temperature while spheroidization was enhanced with increasing ABE temperature. The current work also made use of finite element analysis (FEA) to study the evolution of the equivalent strain distribution across the severely deformed specimens during ABE processing. The FEA results show that the strain distribution in the cross-section after step one (i.e., back extrusion) is inhomogeneous, while it tends to be reasonably homogenous after applying the second step (i.e., constrained back compression). Keywords: A356 Aluminum alloy; ABE; Spheroidization; Finite element analysis