Relationship between the processing parameters and the properties of semi-solid processed Al alloys were studied and microstructure and mechanical properties of semi-solid processed Al parts for automobile application as a function of processing parameters were compared with those of die-cast parts and forged parts. In addition

the locations for the gate during the semi-solid processing were varied to elucidate the distribution of micro-porosities and resulting mechanical properties and the T6 heat treatment on the semi-solid processed part was performed so that the effect of heat treatment on the improvement of mechanical properties could be evaluated in terms of tensile strength

wear properties

etc. Microstructure of semi-solid processed Al part did not show any noticeable micro pores as compared to the microstructure of die-cast part. T6 heat treatment on A319 alloys has greatly improved the hardness as well as the wear resistance. Semi-solid processed A319 part showed slightly higher hardness value than and similar wear resistance to that of forged A332-T4 part. Abrasive type wear behavior was observed in both types of alloys and the friction coefficients of two alloys were similar to be approximately lower than 0.5. In any cases

the heat treated semi-solid processed Al parts showed much improved properties compared to the die-cast parts and could be competitive with forged Al parts. Much improved microstructure with less micro-porosities could be obtained by changing the gate location for the part.