电磁搅拌方式对A356铝合金凝固组织形貌分形维数的影响

Effect of the way of electromagnetic stirring on fractal dimension of solidified microstructure of A356 aluminum alloy

利用分形几何中的分形维数定量表征了铝熔体经低过热度浇注和电磁搅拌作用下半固态合金浆料中初生相的尺寸细化和球化程度.通过OM、Matlab软件平台编制计盒维数法计算程序,研究半固态初生相α-Al形貌的分形特征和电磁搅拌方式对其形貌分形维数变化规律的影响.结果表明,合金的凝固组织具有分形特征,可通过分形维数对初生相尺寸细化和球化程度进行定量表征.初生相的形貌分形维数随搅拌方式由无搅拌、单向连续搅拌过渡到双向连续搅拌时,呈逐渐减小的变化规律,是一个降维的过程.在双向连续搅拌作用下初生相的分形维数最小。

The fractal dimension of fractal geometry was used to quantitatively characterize the size and the spheroidization degree of the primary phase of the semi - solid aluminum alloy after the low over heat casting and electromagnetic stirring. Effect of the way of electromagnetic stirring on the fractal dimension of the primary phase morphology in the alloy was investigated by the OM and the morphologies fractal characteristics of a - Al of semi - solid primary phases was studied,by using the matlab software platform. The results showed that the solidified structure of the alloy has fractal characteristics, which can be quantified by the fractal dimension of its grain size refinement and the degree of spheroidization. The morphological fractal dimension of the primary phase changes with the stirring ways. The fractal dimension of the primary phase is the smallest when the bidirectional stirring is used. In this case the degree of grain refinement is the best.