鐵-30wt.%錳-10wt.%鋁-0.9wt.%碳熱軋合金顯微結構和機械性質之研究

Abstract

鐵-30wt.%錳-10wt.%鋁-0.9wt.%碳合金在熱滾軋狀態下顯微結構為完全的沃斯田鐵相，且在沃斯田鐵相基地內有緻密細微的κ'-碳化物。此合金熱滾軋狀態下即具有優異的強度和延性組合，其最大抗拉強度(UTS)、降伏強度(YS)和延伸率(El)分別為1143MPa、972MPa和75%。在25℃、-50℃、-100℃和-196℃的Charpy衝擊值分別為254、152、103和51焦耳，其顯示出衝擊值隨著溫度的降低而降低且無明顯的延性轉脆現象。值得注意的是，本研究合金在熱滾軋狀態下的拉伸強度、延性和25℃至-196℃的衝擊值均遠優異於熱滾軋狀態下的高強度低合金(HSLA)和相變化誘發塑性(TRIP)鋼。

The microstructure of the Fe-30wt.%Mn-10wt.%Al-0.9wt.%C alloy in as hot-rolled condition is fully austenite, and a high density of fine k'-carbides are formed within the austenite matrix. The ultimate tensile strength (UTS), yield strength (YS), and elongation (El) of the hot-rolled alloy are 1143MPa, 972MPa, and 75%, respectively. It is apparent that the hot-rolled alloy possesses an excellent combination of tensile strength and ductility. The Charpy impact value of the hot-rolled alloy at 25℃, -50℃, -100℃, and -196℃ are 254, 152, 103, and 51 Joules. Obviously, the impact value significantly decreased with decreasing temperature; however, no evidence of ductile-to-brittle transition behavior can be detected. It is worth noting that the tensile strength, ductility, and impact values of 25℃to -196℃are far superior to those of High-strength Low-alloy (HSLA) and Transformation-induced Plasticity (TRIP) steel typically used in hot-rolled condition.