بررسي مقاومت به سايش و سختي آلياژهاي AI-Si ريخته گري شده به روش نيمه جامد

Investigation of the Wear Resistance and Hardness of Al-Si Alloys Cast by Semi Solid Method

Nowadays, the utilization of Aluminium alloys because of their low weight and good mechanical properties is rising. During the last few years the use of semi solid casting method, due to their superior mechanical properties has been growing. In this research, the effect of Si as well as the type of casting on the micros tructure, wear resistance and hardness of Al-Si has been investigated. For this purpose, alloys with different amount of Si i.e., 4, 8 and 14% Si in three conditions, without stirring,with stirring (short and long stirring time) were cast. After casting, the samples were wear tested. The microstructure of all samples was examined with optical microscope and the worn surfaces were investigated by Scanning Electron Microscope. Results show that stirring the melt before casting causes the breaking of dendrites, which leads to globular structure and consequently increases the wear resistance of the material.