Grain refinement of Al–Si alloy (A356) by melt thermal treatment

摘要: Abstract In order to increase the casting quality and material plasticity of hypoeutectic Al–Si alloys, effects melt thermal treatment on solidification structure A356 alloy were analyzed. Unlike conventional addition treatment, no refinements are required during this novel processing. The structural characteristics mechanical properties (plasticity strength) demonstrated. Results quantitative metallorgraphic analysis showed that primary dendrite size obviously reduces grains change into equiaxed ones. However, secondary arm spacing changes little. Experimental results show there is an optimal cooling rate range for in which a maximum microstructure refining effect can be obtained. By optimized parameters obtained with orthogonal experiments, elongation ratio castings increases by 46.2% tensile strength 8.6%. These explained means microheterogeneous theory, result multiplication nuclei treating procedure.