鐵-9鋁-30錳-5鉻-1.2矽合金之相變化

Abstract

我們利用穿透式電子顯微鏡(TEM)研究鐵-9鋁-30錳-5鉻-1.2矽合金之相變化。在淬火狀態下，其顯微結構是肥粒鐵相（α）與細微的D03相混合，其中細微的D03相是在淬火過程中藉由連續規律化所產生。當此合金在450℃至950℃時效熱處理後隨溫度增加，其相變化過程為（α + D03 + α-Mn）→（α + D03 + β-Mn）→（α + β-Mn）→α。這樣的相變化過程與之前被研究的鐵-9.0鋁-30錳-1.2矽合金的相變化過程非常不一樣。在本篇論文中，值得令人注意的是當此合金在650℃時效處理並淬火後，發現有粗大D03與細微D03同時存在，是不曾被其他鐵-鋁-錳-鉻-矽合金研究者發現過。

The phase transformations in the Fe-9.0Al-30Mn-5Cr-1.2Si alloy have been investigated by means of transmission electron microscopy. In the as-quenched condition, the microstructure of the alloy was ferrite phase containing extremely fine D03 particles, where the extremely fine D03 particles were formed by a continuous ordering transition during quenching. When the as-quenched alloy was aged at temperatures ranging from 450℃ to 950℃, the phase transformation sequence as the aging temperature increased was found to be (α + D03 + α-Mn) → (α + D03 + β-Mn) → (α + β-Mn) → α. This phase transformation is quite different from that observed in the Fe-9.0Al-29.5Mn-1.2Si alloy. It is noted that in the present study, the coexistence of the coarse and the fine D03 particles has never been found by other workers in the Fe-Al-Mn-Cr-Si alloys before.