Effect of Cooling Medium on Microstructure and Properties of ZL101A Aluminum Alloy

ZL101A aluminum alloy used in automotive control arm was selected as the research object, and the influence law of four cooling medium condition(air cooling, forced air cooling, oil cooling, water cooling) on the microstructure and properties of ZL101A aluminum alloy after heat treatment were systematically investigated. Optical microscopy(OM) and scanning electron microscopy(SEM) were adopted to observe the microstructure of the alloy, and the tensile test was carried out by using an electronic universal testing machine and the microhardness of the alloy was analyzed using a hardness tester. The results show that water cooling significantly refines grains and forms distinct grain boundaries compared with air cooling. Water-cooled specimens exhibit optimal comprehensive mechanical properties and the highest strength, while air-cooled alloy possesses superior plasticity. The hardness of the alloy first increases and then decreases with the extension of holding time