摘要
对比了高温度和低温度梯度下ＮＡＳＡＩＲ１００单晶的组织和高温持久性能，发现高温度梯度降低单晶中显微疏松含量，减小树枝晶间里和显微偏析程度，使单晶具有较少的γ／γ′共晶和较细的，形状较规则的γ′沉淀．在相同的抽拉速率下，高温度梯度提高铸态ＮＡＳＡＩＲ１００单晶的高温持久寿命可达１１倍多，固溶处理进一步改进单晶的组织和高温持久性能．
The microstructure and high temperature stress rupture properties of a nickel-base single crystal superalloy NASAIR100 cast in both high and low thermal gradients have ben investigated comparatively. It was found that the high thermal gradient casting enhanced reductions in dendrite arm spacing and in the amount of casting porosity. The high thermal gradient cast single crystals possessed finer,more regular γ′Precipitates and less γ/γ′cutectic. With the same withdrawal rate, the high thermal gradient casting was found to improve the average stress rupture life of as-cast NASAIR100 to the extent of 12 times longer than that of the low thermal gradient casting. Solution heat treatments provided further improvements in the microstructure and stress rupture properties.
出处
《材料研究学报》
EI
CAS
CSCD
1995年第3期213-218,共6页
Chinese Journal of Materials Research
关键词
温度梯度
单晶
组织
性能
固溶处理
合金
thermal gradient, NASAIR100 single crystal, solution heat treatment, microstructure and mechanical property
