Microstructure and Mechanical Properties of ZA27 Alloy Rheo-Diecasting Process Fabricated by Self-Inoculation Method

Abstract

Semisolid slurry of ZA27 alloy was prepared by Self-inoculation Method (SIM), the effects of isothermal holding parameters on microstructures of rheo-diecasting were researched, and the mechanical properties of ZA27 rheo-diecastings were tested. The results indicate that the dendritic microstructure of ZA27 alloy formed by permanent mold casting can be significantly modified by RDC with SIM, and obtain fine spherical microstructures. After comprehensive consideration, the suitable melt treatment temperature for the ZA27 alloy semisolid processing is 550~560°C. The isothermal holding process of ZA27 alloy slurry has great effect on primary α-Al particles (α 1 ), while has little effect on the microstructure of secondary solidification in the process of thin-walled rheo-diecasting, and the suitable isothermal holding time of semisolid slurry for rheo-diecasting is 3 min. Compared with HPDC, the RDC process can increase the tensile strength of ZA27 alloy by more than 6.9%, with a maximum increase of about 12.5%. The best performance die casting can be obtained when the slurry holding time is 3-5 min.

Effects of Process Parameters on Microstructure and Mechanical Properties of Semi-Solid Al-7Si-0.5Mg Aluminum Alloy by Gas Induced Semi-Solid Process

“…Initially, semi-solid processing techniques, such as mechanical stirring method [5,6] and electromagnetic stirring method [7,8], were mainly used for experimental research with few industrial applications. In recent years, researchers have designed preparation methods with simple equipment and low cost, such as gas induced semi-solid process [9,10], selfinoculation method [11], rapid slurry forming [12,13], cooling ramp method [14], serpentine channel method [15], helical groove method [16], etc., and the formation mechanism of the slurry is also being continuously improved and developed [17,18].…”