摘要
对单晶高温合金DD6进行吹砂处理,然后在真空条件下对单晶合金吹砂试样进行标准热处理以及在1000-1250℃温度范围内加热4h-16h,采用SEM、HRSEM以及TEM研究了DD6合金的表面再结晶行为。结果表明,等轴状再结晶在γ′相完全溶解的γ相中形成,而胞状再结晶在γ′相部分溶解的区域形成。胞状再结晶由胞状粒子组成,而胞状粒子由立方化的γ′相,长条状的γ′相以及γ+γ′组成。等轴状再结晶与胞状再结晶共存是冷变形单晶合金在低于固溶温度条件下加热时的再结晶特征。加热温度高于1150℃,随着加热温度的升高,等轴状再结晶区域逐渐增大,而胞状再结晶区域逐渐减小。在固溶温度条件下。
The samples of single crystal superalloy DD6 are grit blasted and then heat treated either with the standard heat treatment procedure or in the temperature range of 1 000-1 250 ℃ for 4-16 h at vacuum atmosphere, then the recrystallization behavior of DD6 alloy is investigated. The results show that the equiaxed recrystallization grains form in the 7 phase region where the as-cast γ＇ phases have been dissolved completely, and cellular recrystallization forms in the region where the ascast γ＇ phases have been dissolved partially. The cellular recrystallization area consists of cellular grains, and the cellular grain consists of cubic γ＇ phase, lamellar γ＇ phase and γ＋γ＇. The coexistence of the equiaxed recrystallization zones and cellular recrystallization zones is a re- crystallized characteristic of the cold worked single crystal samples which are heat treated at a temperature lower than the solu- tion temperature. When the heating temperature is higher than 1 150 ℃, with the increase of heat treating temperature, the equiaxed recrystallization zone expands, whereas the cellular recrystallization zone shrinks. All the deformed regions are consumed by equiaxed recrystallization after annealing at solution temperature.
