模具结构对模压变形超细晶5052铝合金拉伸性能的影响

Influence of die construction on tensile properties of ultrafine grain 5052 aluminum alloy processed by repetitive groove pressing

在自制的新型组合式模具上进行两种不同结构模具下的反复模压变形制备超细晶5052铝合金板材,并研究了模具结构对其拉伸性能的影响。结果表明:限制模压(Constrained Groove Pressing,CGP)变形和非限制模压(Unconstrained Groove Pressing,UGP)变形均能够显著强化5052铝合金,抗拉强度随变形道次的增加而单调递增。5052铝合金经CGP和UGP变形后均呈现韧性断裂特征,CGP变形试样的伸长率随变形道次的增加基本保持不变,且在变形3道次后略有提高;UGP变形试样的伸长率随变形道次的增加不断减小,且显著低于CGP变形试样。CGP与UGP变形试样拉伸性能上的差异是由其晶粒细化能力上的本质差异决定的,CGP变形试样具有更为优异的综合力学性能。

Tensile properties of ultrafine grain 5052 aluminum alloy processed by repetitive groove pressing, using a novel self-designed groove pressing die, were investigated. The results show that both constrained groove pressing （CGP） and unconstrained groove pressing （UGP） are both good for strengthening the 5052 aluminum alloy, and the ultimate tensile strength increases with the increasing of pass number. Fracture surface morphology demonstrates that the fracture mode is ductile. The elongation of the sample processed by CGP keeps constant approximately, and increases slightly after the third pass. But the elongation of the UGP processed sheets decreases continually with the increasing of pass number, and much lower than that of the CGP. The differences in tensile properties of the CGP and UGP processed uhrafine grain 5052 aluminum alloy are essentially attributed to the difference in grain refinement by CGP and UGP. Compared with UGP, CGP processed sheets exhibit better comprehensive mechanical properties.