The effect of pressure and pouring temperature on the porosity, microstructure, hardness and yield stress of AA2024 aluminum alloy during the squeeze casting process

Abstract

The effect of pressure and pouring temperature on the microstructure, porosity, hardness and yield stress of AA2024 aluminum alloy during squeeze casting process was investigated. At a constant pouring temperature (700°C), by increasing the applied pressure up to 140MPa, the hardness increased from 125 HBN to 152 HBN while the yield stress increased from 235MPa to 340. Moreover, by increasing the applied pressure (to 140MPa) and reducing the pouring temperature (at 700°C), the DAS size and the porosity diameter decreased to 12.5 and 0.25μm, respectively. Thus, the density increased to 2.75 (g/cm3). At a pressure of 140MPa and 700°C, an ultra-fine grain structure with an average grain size of 80nm was observed. At squeezing pressures greater than 70MPa, the effect of pouring temperature was less important.