中文摘要：

采用多重分形理论研究半固态A356铝合金初生相,计算了其多重分形谱。结果表明,半固态A356铝合金初生相具有多重分形特征。螺旋角度为540°时,在4组螺旋角度试验中其多重分形谱宽Δα最小,初生相分布最均匀集中。浇注温度为635℃时,在4组浇注温度试验中其多重分形谱宽Δα最小,初生相分布最均匀集中。所有计算的8组试验的谱函数对称度Δf均大于0,谱函数f（α）形态都呈向左的钩状,其计算大概率子集占主要地位。多重分形谱谱宽Δα,谱函数对称度Δf和谱函数f（α）等参数可以定量表征其分布均匀性的差异,从一个新的角度去描述半固态微观组织特征。

英文摘要：

Characteristics of primary phases in semi-solid A356 aluminum alloy was analyzed using multifractal theory,and the multi-fractal dimension spectrum was calculated.The results show that the primary phase in semi-solid A356 aluminum alloy exhibits multi-fractal characteristics.When helix angle in helical curve duct is 540°,the spectral width（Δα）of multi-fractal spectrum is the narrowest in the four groups of helix angle tests,and the distribution of primary phase is the most uniform.When pouring temperature is 635 ℃,the spectral width（Δα）of multi-fractal spectrum is the narrowest in the four groups of pouring temperature tests,and the distribution of primary phase is the most uniform and concentration.All morphology of spectral function f（α）is hooked to the left because of all spectral function symmetryΔfof eight group tests more than 0,and high probability subset is dominant.Parameters of multi-fractal dimension spectrum such as spectral widthΔα,spectral function symmetryΔfand spectrum function f（α）can be characterized by the quantificational dissimilarity of uniformity,which can describe the characteristics of semi-solid microstructure from a new point of view.