AGING TEMPERATURE EFFECT on HARDNESS and MICROSTRUCTURE of A357 ALUMINIUM ALLOY PART WHICH PRODUCED by GDC and LPDC

A357 aluminium alloy commonly used in automotive, energy, aerospace and engineering applications. In this study, A357 aluminium alloy parts produced by Gravity Die Casting (GDC) and Low Pressure Die Casting (LPDC) methods were used. T6 heat treatment was applied. Firstly, samples are solutionized at 540o C during 7 hours, then quenched at room temperature water. After that, artificially aged at 150°C and 170°C aging temperatures. Their Vickers hardness changes have observed. For two different casting methods, the hardness increases in the first few hours according to the untreated conditions. Also, dendritic microstructure has changed to homogeneous microstructure after heat treatment. At the beginning, the part which produced by Low Pressure Die Casting method shows higher hardness, lower secondary dendritic arm spacing (SDAS) value and lower porosity against gravity die cast part. After T6 heat treatment LPDC part’s advantages against GDC method has partially disappeared