鐵-8.8鋁-30錳-6鉻-1.0矽-1.0碳合金之相變化

Abstract

我們利用穿透式電子顯微鏡研究鐵-8.8鋁-30錳-6鉻-1.0矽-1.0碳合金之相變化。在淬火狀態下，此合金的顯微組織為單一的沃斯田鐵相。當此合金在550至1000℃時效熱處理後隨溫度增加，其相變化過程為((Fe, Mn, Cr)7C3+D03)→((Fe, Mn, Cr)7C3+B2)→((Fe, Mn, Cr)7C3+α) +γ→((Fe, Mn, Cr)7C3 +γ) →γ，可以明顯地發現沒有(Fe, Mn, Cr)23C7碳化物的產生在此成份的合金。這樣的相變化過程與之前被研究的鐵-8.8鋁-30錳-6鉻-1.0碳合金的相變化過程非常不一樣。此外，650℃時的B2相擁有比在750℃時的α相較多的矽含量，因此，造成在650℃時效處理所產生的D03相會比在750℃時效處理還大。

The Phase transformations in the Fe-8.8Al-30Mn-6Cr- 1.0Si-1.0C alloy have been examined by means of transmission electron microscopy. In the as-quenched condition, the microstructure of the alloy was the single phase austenite. When the as-quenched alloy was aged at temperatures ranging from 550 to 1000℃, the phase transformation sequence as the aging temperature increased was found to be ((Fe,Mn,Cr)7C3+D03)→ ((Fe,Mn,Cr)7C3+B2)→((Fe,Mn,Cr)7C3+α) +γ→((Fe,Mn,Cr)7C3 +γ)→γ, in which no (Fe,Mn,Cr)23C7 carbides could be found in the present alloy. These results are quite different from that observed in the Fe-8.8Al-30Mn- 6Cr-1.0C alloy. Besides, since the B2 phase present at 650℃ contains much more silicon than the ferrite phase present at 750℃, the size of the D03 domains was much larger than that of the alloy aged at 750℃ and then quenched.