- 學位論文
不同熱處理條件對CM681LC鎳基超合金單方向凝固鑄造高溫氧化行為研究
Effects of Different Heat Treatment Temperatures on High Temperature Oxidation Behavior of Directionally Solidified CM681LC Ni-Based Superalloy
摘要
本實驗採用CM681LC鎳基超合金以單方向鑄造在不同固溶溫度之熱處理條件下，進行長時間的高溫恆溫氧化。首先將CM681LC鑄錠經過線切割，變成圓柱狀的試棒，之後再以單方向凝固鑄造製作出單方向晶的試棒。接下來再將單方向晶的試棒進行熱處理，其中熱處理條件主要差異為固溶熱處理，本實驗溫度參數設定如下，為1185℃/4hr1038℃/2hr871℃/20hr與1270℃/4hr1038℃/2hr871℃/20hr。之後再將熱處理完的試棒裁切成試片並研磨至5mm的厚度，進行高溫恆溫氧化實驗模擬陸用型渦輪葉片在高溫環境下作業的狀態。最後將實驗結果後的氧化試片進行SEM、EMPA、EDX之深入分析；在材料原有本質不變的形況下，沒有額外添加合金元素或是coating的塗層保護下，希望可以調整出更良好的抗氧化性質，進行深度的探討。
並列摘要
In this experiment, according to the different heat treatment conditions of directionally solidified CM-681LC Ni-based superalloy, the relationship between the difference of microstructure and the high temperature oxidation performance was compared by high temperature oxidation experiment. First, different ambient temperature conditions thermostatic high temperature oxidation test, the mass change was observed which generates oxidation. At last, the microstructures and microstructures of the oxides were analyzed by SEM, EDS and EPMA. The data of the experiment were analyzed and discussed. The activation energy at 1270℃ was 176 (KJ · mol-1) at a minimum of 284 (KJ · mol-1)，and the activation energy at 1185℃ is 282 (KJ · mol-1), the highest is 152 (KJ · mol-1),The activation energy of Al3+ diffusion in the oxide layer is 145.6 ~ 177.9 (KJ · mol-1), which indicates that the oxidation process of CM681LC is restricted by the diffusion of Al2O3 in the oxide layer.