研究了不同的型壳保温温度对一种铸造单晶高温合金DD98铸态组织、热处理组织和持久性能的影响。结果表明,随着上下区型壳保温温度的升高,固液界面前沿的温度梯度增大,而糊状区的宽度减小。铸态下,随着上下区型壳保温温度的升高,其一次和二次枝晶间距均减小,枝晶间和枝晶干上的γ′尺寸差别减小,并且枝晶间的γ′形状也逐渐变得规则,合金的显微偏析程度降低。热处理后,高的型壳保温温度可获得尺寸细小的γ′和较少的残留共晶。合金的持久寿命随着型壳保温温度的升高而增加,但相应的持久延伸率降低。 The effects of different shell temperature on the as-cast microstructure, heat-treated structure and ductility of a cast single crystal superalloy DD98 were investigated. The results show that the temperature gradient at the front of the solid-liquid interface increases and the width of the mushy zone decreases with the increase of the holding temperature of the upper and lower shell. Under the as-cast condition, the primary and secondary dendrite spacing decreases with the increase of the holding temperature of the upper and lower shell, the difference of γ ’size between dendrite and dendrite decreases, and the interdendritic γ’ The shape also gradually becomes regular, and the degree of micro segregation of the alloy decreases. After heat treatment, a high shell holding temperature results in a small size of γ ’and less residual eutectic. The longevity of the alloy increases with the holding temperature of the shell, but the corresponding permanent elongation decreases.