Effects of Forming Processes on Microstructures and Mechanical Properties of A356 Aluminum Alloy Prepared by Self-inoculation Method

Abstract

Semisolid slurry of A356 aluminum alloy was prepared by Self-Inoculation Method (SIM), and the microstructures and solidification behavior of rheo-forming process in different forming processes were researched. The results indicate that semisolid slurry of A356 aluminum alloy can be prepared by Self-Inoculation Method at 600ºC. Primary α-Al particles with fine and spherical morphology are uniformly distributed when the isothermal holding time of slurry is 3 min. The different forming processes for semisolid rheo-forming can be regarded as the effect of cooling rate on rheo-forming. The primary particle sizes and shape factors are gradually increasing with the increase of cooling rate. The sizes of secondary particles are gradually increasing with the decrease of cooling rate, and the amount of secondary particles in the same areas are gradually decreasing with the decrease of cooling rate. The morphologies of eutectic Si are gradually coarsening from fibrous to needle-like in different forming processes, while the sizes and the lamellar spacing of the eutectic Si are gradually increasing with the decrease of cooling rate. The mechanical properties of the semisolid forming components are gradually increasing with the increase of cooling rate and forming pressure.

Current Progress in Rheoforming of Wrought Aluminum Alloys: A Review

“…For example, in some methods, such as SEED [51] or CSIP-RCS [52], the melt scours the channel or crucible intensely during pouring, causing entrainment defects. In addition, in some methods like LSPSF [53], SIM [54], and SCP [55], the melt flows through a certain length of pouring channel under the combination action of pouring and gravity while scouring the inner wall of the pouring channel intensely, leading to entrapment defects. These defects can also occur when the melt flowing out of the pouring channel is injected directly into the slurry collection crucible, mold cavity or injection chamber due to strong turbulence resulting from its high flow velocity.…”