Influence of pulse current on the shape of non-metal phases during heat treatment processes

The effect of pulse current on the shape of non-metal phases in solid metals,such as Al-Si alloys and ductile cast irons,was studied by applying pulse current at room-temperature and high temperature and compared to normal heat processing.The results show that pulse current accelerates the granulation of coarse band-form eutectic silicon in the Al-Si alloy.The diameter of original graphite in the ductile cast iron treated by pulse current does not increase obviously,the average round-shaped degree of graphite increases a little,and some spherical graphite appears in the structure.The behavior of dislocations adjacent to non-metal phases and the diffusion of atoms by the action of pulse current are main reasons for the shape of non-metal phases.