Study On Microstructure And Properties Of AXJ530 Magnesium Alloys

The present work investigated the castability, corrosion-resistance, mechanical properties at room and elevated temperatures and creep behavior of Mg-5Al-3Ca-0.17Sr (AXJ530) magnesium alloys. The castability experiment was carried out by using UBE 650T die cast machine. The microanalysis was performed by optical microscopy (OM), image analysis apparatus (Olympus) with a Leco image analysis software, inductively coupled plasma analyzer (ICP), scanning electron microscopy (SEM) with energy dispersive X-ray analyses (EDAX). The corrosion behavior was studied by Salt spray test and Solatron 1287+1260 electrochemical test system. The creep behavior was studied by creep data collection system.There were 10 groups of technological parameters for die cast. After analyzing casting flaws of diecastings of each technological parameters and studying on the influence of pouring temperature, mould temperature and shot velocity on castability, it has optimal technological parameters were determined as follows: pouring temperature 680oC, mould temperature 250 oC, shot velocity 1.5m/s.The microstructure of as-cast AXJ530 alloy consists of dendriticα-Mg and grain-boundary eutectic phase which has a lamella structure consisting of alternating layers of magnesium and an Mg-Al-Ca intermetallic phase. There are more fine grains in die-cast alloy.Corrosion test results indicated that influence of Fe, Ni and Cu on corrosion velocity of AXJ530 magnesium alloys in different conditions was similar. The corrosion resistance of AXJ530 magnesium alloy is unaffected by specimens containing 69ppm or less, of Fe or 100ppm or less, of Cu in both the 5%NaCl salt water immersion and the 5%NaCl salt spray environment. However, it is deteriorated by specimens containing more than 3ppm of Ni in both the 5%NaCl salt water immersion and the 5%NaCl salt spray environment. The current density of polarization curve varied similarly to corrosion rate in the 5%NaCl salt water immersion test and the 5%NaCl salt spray test, but almost there is no obvious effect of Cu on current density.AXJ530 magnesium alloy exhibits good strength at high temperatures. The ultimate...