Effect of Section Size on the Microstructure of Thin-walled Specimen of DD6 Single Crystal Superalloy

摘要:

制备不同截面尺寸的单晶高温合金精铸薄壁试样，研究了截面尺寸对DD6单晶高温合金精铸薄壁试样组织的影响规律。结果表明：随着截面尺寸的减小，铸态单晶高温合金精铸薄壁试样一次枝晶间距和共晶含量出现先减小后增大的现象，热处理态单晶高温合金精铸薄壁试样枝晶干γ’相平均尺寸逐渐减小。截面尺寸的适当减小有利于减轻枝晶元素偏析程度，但当截面尺寸减小到0.5 mm时，枝晶元素偏析程度反而增大

Abstract:

Thin-walled specimens of the DD6 single crystal superalloy with different thicknesses were prepared using Bridgman method. The effect of section size on the microstructure of the thin-walled specimens of DD6 single crystal superalloy was investigated. The results show that with the reduction of section size, the primary dendrite arm spacing and the eutectic percent of the thin-walled specimen as-cast first decrease and then increase, and the average size of γ’ phase in the dendritic core of the thin-walled specimen after heat treatment declines gradually. The appropriate decrease in section size can reduce the degree of interdendritic segregation, but when the section size is reduced to 0.5 mm, the degree of interdendritic segregation increases