Abstract: The influence of the low temperature melt (LTM) structure on solidification structure of the sample with melt thermal treatment (MTT) process was studied. And the mechanism of the MTT process was analyzed with cluster theory. It is shown that the final solidification structure is dependent mainly on the structure of LTM. Dendrites will appear in the solidification structure if the structure of LTM is dendritic before MTT. Otherwise, nondendritic grains will appear in the solidification structure. And the lower the temperature of LTM, the more remarkable the effect of the LTM structure is.

Key words:  aluminum alloy melt; solidification structure; MTT; cluster