High Temperature Impact Deformation and Dislocation Substructure of 6061-T6 Aluminum Alloy

鋁合金（6061-T6）在高溫撞擊下之塑變行為與差排結構分析

李偉賢(Woei-Shyan Lee) ； 唐子超(Zih-Chao Tang)

《中國機械工程學刊》 34卷4期 (2013/08) Pp. 263-270

摘要

本研究利用哈普金森高速撞擊試驗機研究6061-T6鋁合金在高溫撞擊下之塑性變形行為與差排結構特徵。變形時應變速率控制在1×10^3～5×10^3 s^(-1)之間，溫度則為100～350ºC的範圍。結果顯示，鋁合金之流變應力、加工硬化率及應變速率敏感性係數皆隨應變速率的增加而增加；但卻隨溫度的增加而降低。而溫度敏感性係數則隨溫度及應變速率的上升而上升。在所測試之變形條件下，最大之熱活化能為64.8 kJ/mol。實驗所得之塑性變形行為可藉Zerilli-Armstrong組構模式來準確的描述。差排結構分析顯示，應變速率的增加導致差排密度的提升，進而降低差排環的尺寸；然溫度卻有相反的效應。而高的差排密度及小的差排環尺寸則反應出高的流變應力。

並列摘要

The high temperature deformation behaviour of 6061-T6 aluminum alloy is investigated at strain rates ranging from 1x10^3 ~ 5x10^3 s^(-1) and temperatures of 100 ~ 350ºC using a compressive split-Hopkinson pressure bar system. It is found that the flow stress, work hardening rate and strain rate sensitivity all increase with increasing strain rate or decreasing temperature. Moreover, the temperature sensitivity increases with increasing strain rate and increasing temperature. The activation energy varies as a function of the strain rate and temperature and has a maximum value of 64.8 kJ/mol under the present loading conditions. The dislocation density increases, and the cell size decreases, as the strain rate is increased or the temperature decreased. The change in the dislocation density and cell size causes a corresponding change in the flow stress.

並列關鍵字

6061-T6 alloy ； impact ； high temperature deformation ； strain rate effect ； dislocation