As-quenched Microstructures of Cu3-xMnxAl (x=0.1, 0.2, 0.3, 0.4) Alloys.

Abstract

在淬火狀態下，合金A（Cu2.9Mn0.1Al）的淬火顯微結構為D03和γ1΄麻田散混合相。隨著錳含量的上升，合金B（Cu2.8Mn0.2Al）和合金C（Cu2.7Mn0.3Al）其淬火顯微結構改變為（D03＋L-J）的混合相。而當錳含量添加到超過8 at％時，合金D（Cu2.6Mn0.4Al）其淬火顯微結構改變為（D03＋L21＋L-J）的混合相。同時Ms溫度也將隨著錳成份的上升而降低；相反地，L-J相卻隨著錳成份的增加而增加。 當合金B和C於淬火時所產生的 A2→B2→D03 連續規律相變化，將伴隨著a/2<100> 以及a/4<111>反向晶界的發生，其中a/4<111>反向晶界尚未被其他學者在Cu-Al-Mn合金發現過；而在合金D中並無a/4<111>反向晶界被發現到，此證明a/4<111>反向晶界能量會隨錳含量的增加而增加。

The as-quenched microstructure of the alloy A (Cu2.9Mn0.1Al) was D03 phase containing plate-like γ1΄ martensite. When the manganese content was added to the 8 at%, the as-quenched microstructures of alloys B (Cu2.8Mn0.2Al) and C (Cu2.7Mn0.3Al) were changed to (D03＋L-J) phases. However, when manganese content was added over 8 wt. pct. further, the as-quenched microstructure of the Alloy D (Cu2.6Mn0.4Al) was a mixture of (D03＋L21+L-J) phases. Thus, the martensite start（Ms） temperature was decreased with increasing the manganese content. On the contrary, the amount of the L-J particles was increased with increasing the manganese content. Both of the a/2<100> and the a/4<111> APBs could be observed by the A2→B2→D03 continuous ordering transition during quenching in the both alloy B and alloy C. The a/4<111> APBs have never been found by other workers in the Cu-Mn-Al alloys before. Besides, no evidence of the a/4<111> APBs could be observed in the as-quenched microstructure of the alloy D. It clearly shows that the a/4<111> APBs was increased with increasing the manganese content