再结晶退火对ECAP变形5083铝合金力学性能的影响

Recrystallization annealing effect on mechanical behavior of ECAP 5083 aluminum alloy

为改善5083铝合金的力学性能,先后对其进行一道次等通道转角挤压处理及再结晶退火处理,再进行拉伸实验,分析变形温度、变形速率对合金伸长率和抗拉强度的影响,并观察合金的断口形貌。结果表明,在拉伸温度为100℃,应变速率为6.67×10-4s-1时,合金的抗拉强度最高,达到319.7 MPa;当拉伸温度为300℃,应变速率为1.67×10-4s-1时,合金的伸长率最大,达到75.8%。在拉伸变形过程中,合金出现应变硬化和应变软化现象,并且伴随有锯齿形流变现象。拉伸试样的断裂形式宏观表现为韧性断裂,微观形式为穿晶断裂,断口形貌由韧窝组成。随着变形温度的升高,韧窝的数量增多,尺寸变大,分布变均匀。

This paper is concerned with improving the mechanical behavior of 5083 aluminum alloy. The specific improvement is obtained by performing tensile tests after subjecting the alloy to processes consisting of one pass of equal channel angular extrusion processing and the recrystallization annealing treatment; and identifying the effect of the deformation temperature, deformation rate on elongation and tensile strength and thereby observing the fracture morphology of alloy. The results suggest that with the temperature of 100 ℃ and the rate of 6.67 × 10 -4 s - 1, the alloy has the highest tensile strength, up to 319.7 MPa; at the temperature of 300 ℃ and the rate of 1.67 × 10 -4 s-1, the alloy has the longest elon- gation, up to 75.8% ; the tensile deformation tends to leave the alloy subjected to strain hardening and strain softening behavior, along with the jagged rheological behavior; the fracture mode of the tensile specimen is characterized by ductile fracture in macro form and transgranular fracture in microscopic form, with the fracture consisting of toughening nest; and the increasing deformation temperature is ac- companied by an increasing number of toughening nests, a large size, and a more uniform distribution.