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采用AlTiC作为7050铝合金的细化剂,并在铸造中引入高频超声波,通过比较不同试样表面微观组织的晶粒尺寸以及试样中Ti和C元素的分布等特征,研究超声波对AlTiC细化剂细晶效果的影响及其作用机理.研究结果表明:施加高频超声波能够加速TiAl3相的溶解,提高TiC粒子团与铝溶液的润湿性;粗大晶粒的内部存在一个或多个Ti原子偏聚区;而细小晶粒中Ti原子的偏聚则集中在晶界上,其晶内保持着一个相对较低的质量分数;施加高频超声波能够抑制TiC粒子团间的融合,减小Ti原子偏聚区的面积以及质量分数,进而提高TiC粒子团的形核能力,使所得的金属凝固组织更为细小、均匀.
AlTiC was used as the refiner of 7050 aluminum alloy, and high frequency ultrasonic was introduced into the casting. By comparing the grain size of microstructures on different samples and the distribution of Ti and C elements in the samples, The effect and mechanism of agent on the crystallization of TiC were studied.The results show that the application of high frequency ultrasonic wave can accelerate the dissolution of TiAl3 phase and improve the wettability of TiC particles and aluminum solution.The existence of one or more Ti At the same time, the segregation of Ti atoms in the fine grains is concentrated on the grain boundaries, and a relatively low mass fraction is maintained in the grains. The application of high frequency ultrasonic waves can inhibit the fusion between TiC particles and decrease Ti atomic segregation zone area and mass fraction, and thus improve the nucleation ability of TiC particles, the resulting metal solidification microstructure is more small and uniform.