- 學位論文
鐵-4鋁-3鉻-6鎳-16錳-0.2碳合金相變化
Phase Transfomation of the Fe-4Al-3Cr-6Ni-16Mn-0.2C Alloy
摘要
本研究主要針對鐵-4鋁-3鉻-6鎳-16錳-0.2碳合金進行顯微組織分析。其結果顯示：合金鑄件為具FCC結構之單相沃斯田鐵，經950~1150℃之固溶處理，晶粒會隨溫度增加而變大，晶格常數a＝0.386nm。當進行450~550℃短時間之時效處理後，未發現析出物。若時間增加至8小時，則晶界開始析出M23C6碳化物，晶格常數為1.060nm。而16小時後，晶界除了觀察到M23C6亦發現DO3，晶格常數為0.531nm。若時間增加至64小時，只觀察到M23C6碳化物晶格常數1.088nm。合金經750℃加熱8小時之時效處理後，基地內觀察到有M23C6碳化物析出，晶格常數a＝1.090nm。在850℃短時間熱處理，並未發現任何析出物。因此，合金在450~750℃時效處理時，晶界相變化為γ→γ＋M23C6→γ＋M23C6＋DO3→γ＋M23C6，基地之相變化為γ→γ＋M23C6。 關鍵字：鐵鋁錳鎳鉻碳合金、相變化、M23C6碳化物、DO3
並列摘要
The main purposes of the present studies are to investigate the phase transformation of the Fe-4Al-3Cr-6Ni-16Mn-0.2C Alloy. The results of the study are as follows: When the being SHT at 950~1150℃, the microstructure was a single austenite phase with twins. The lattice grow up with increasing the SHT temperature to 950 to 1150℃, the lattice parameter was a=0.386nm. During aged at 450-550 ℃ for a hour microstructure was a single austenite phase .For 8 hours, some M23C6 carbides were observed within the grain boundaries. When the specimen aged at the temperature to the 650℃ for 8~16 hours, the microstructure was a single austenite phase with twins. Some M23C6 carbides and DO3 were observed within the grain boundaries, the lattice parameter of DO3 was a=0.531nm. Prolonged the aged time for 64 hours, only M23C6 carbides were observed within the grain boundaries. The lattice parameter was a=1.088nm. When the specimen aged at the temperature to the 750℃ for 1 hour, some M23C6 carbides were observed within the austenite matrix. The lattice parameter was a=1.090nm..Increasing the aging temperature to the 450℃~750℃, a γ →γ＋M23C6 phase transition was found, and a γ →γ＋M23C6→γ＋M23C6＋DO3→γ＋M23C6 phase transition found on the grain boundaries. Keyword：Fe-Al-Mn-Ni-Cr-C alloy, Phase Transformation, M23C6 carbides,DO3