The microstructure of a single crystal superalloy aging heat treatments
摘 要：为了学习老化的影响，与倔强的元素和最佳的变老热治疗政体的高内容在单个水晶 superalloys 的微观结构上加热治疗，包含 22 的单个水晶 superalloy ?wt% 倔强的元素被调查。结果证明为试验性的合金，为 25 弄平 homogenization 答案热治疗 ? h 不能一致 alloying 元素完全。在主要老化热治疗期间，阶段变得更大并且转到常规立方体。更高的老化温度导致更大的立方体。在 1120 点为有主要老化热的标本对待 ? 獴????????? 吗？？To study the influence of aging heat treatments on the microstructure of single crystal superalloys with high content of refractory elements and optimal the aging heat treatment regimes, a single crystal superalloy containing 22 wt% refractory elements was investigated.Results show that for the experimental alloy, even the homogenization-solution heat treatment for 25 h cannot homogenize the alloying elements completely. During primary aging heat treatment, γ＇ phase grows larger and turns to regular cubes. Higher aging temperature induces larger γ＇ cubes. For specimens with primary aging heat treated at 1120 ℃,γ＇ morphology does not change apparently during secondary aging heat treatment. For specimens with primary aging heat treatment at 1150 ℃,γ＇phase in interdendrite grows obviously comparing with that in dendrites. By analyzing the precipitating kinetics of γ＇phase, it is found that owning to the dendrite segregation and different aging heat treatment temperatures, γ＇ phase at different regions grows under the control of different factors at different aging heat treatment stages. The two controlling factors that are driving forces of phase transformation and element diffusion rate induce obviously different growth rates of γ＇ phase. As a result, the γ＇-precipitating behaviors are variable based on different solute concentrations and aging temperatures. For advanced single crystal superalloys that are supposed to be used at relatively high temperatures, the final γ＇ size after aging heat treatment is suggested to be close to the crossing point of diffusion controlling curve and driving force controlling curve corresponding to the serving temperature. And then,high-temperature properties can be improved.
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