鐵-8鋁-30錳-1碳-3銅合金相變化

Phase Transformations of Fe-8Al-30Mn-1C-3Cu Alloy

彭耀儒(Yao-Ru Peng)

指導教授 ： 趙志燁

國立屏東科技大學/工學院/機械工程系所/碩士(2009年)

https://doi.org/10.6346/NPUST.2009.00197

摘要

添加3%銅於鐵-8鋁-30錳-1碳合金中，經950℃/30分鐘固溶處理後，顯微結構為單相沃斯田鐵帶有雙晶，晶格常數a=0.367nm。450℃/96小時時效，細微κ' 相碳化物在基地被發現，基地產生了γ→γ＋κ' 相變化。經550℃/96小時時效處理顯微結構為γ＋κ' ，時效時間延長到144小時，顆粒狀的κ相碳化物開始於晶粒邊界上析出。時效650℃/16小時，細微κ' 相會集中在晶粒邊界附近，粗大顆粒狀κ相在晶粒邊界上出現，並且隨著時效時間的增加，粗大顆粒狀κ相碳化物會轉變成γ＋κ的層狀結構(lamellar structure)。時效溫度在550℃~650℃有一晶界相變化為γ→γ＋κ。長時效後，銅元素會與κ相碳化物化合，使κ相含銅量上升，也造成析出時間延長與晶格常數的增大。κ相晶格常數a=0.379~0.382nm、κ' 相晶格常數a=0.372~0.375nm。

關鍵字

相變化 ； 沃斯田鐵 ； 銅 ； κ相碳化物

並列摘要

The microstructure of the as-quenched specimen was a single austenite phase with annealing twins. The lattice parameter of austenite phase is a=0.367nm. Being aged at 450℃ for a various time, the fine κ'-phase carbides were found within the matrix coherently. Increasing the aging temperature to 550~650℃, the γ＋κ' phase transition occurred within the matrix. However, prolonged aging time more than 144 hours, some coarse κ-phase carbides were precipitated on the grain boundaries, the lattice parameter of the carbides being a=0.379nm. It reveals that the coarse κ carbides grew into the adjacent γ grains through a γ → γ + κ reaction. The mixture of (γ+κ carbide) had a lamellar structure. Based on the SEM-EDS examinations, the κ-phase carbides were possessed the higher copper, indicating that the copper will play an important role on the phase transition sequences of grain boundary. In addition, the Cu-richer κ-phase carbides would posses higher lattice parameter in the range between 0.379~0.382nm. The lattice parameter of the κ'-phase carbides being a=0.379nm.

並列關鍵字

Microstructure ； Austenite ； Cu ； κ-phase carbides

參考文獻

[9] 趙志燁、葉嘉雯，2007，「鐵-9鋁-28錳-1.3碳-5鉻合金相變化」，國立屏東科技大學機械工程研究所碩士論文。

[1] Wei-Chun Cheng and Hsin-Yu Lin: “The precipitation of FCC phase from BCC matrix in an Fe–Mn–Al alloy”, Mater. Sci. Eng., A323, 2002, pp. 462-466

[2] R. Umino, X.J. Liu, Y. Sutou, C.P. Wang, I. Ohnuma, R. Kainuma, and K. Ishida, Experimental Determination and Thermodynamic Calculation of Phase Equilibria in the Fe-Mn-Al System, J. Phase Equilb. Diffus., 2006, 27(1), p 54-62.

[5] G. Frommeyer, H. J. Habrock, J. E. Wittig, J. Geenen, M. Kreuss, ”Investigations on phase transformations and B2-DO3 superlattices in ordered iron aluminium alloys by fim-atom probe and TEM”, Scripta Metall. Vol 24, 1990, pp. 51-56

[11] Kao, C. H., and Wan, C. M. (1988)“Effect of Manganese on the Oxidation of Fe-Mn-Al-C alloys”, Journal of Materials Science ,23 ,744-752.