(1. 大连理工大学 材料科学与工程学院，大连116024；
2. 大连理工大学 机械工程学院，大连 116024；
3. 大连理工大学 汽车工程学院，大连 116024)
摘 要: 基于6061-T6铝合金在高温变形过程中的动态回复、动态再结晶及变形硬化特性，分析其在不同温度阶段的黏塑性特征，在高温阶段进一步引入软化因子修正传统Field-Backofen模型，使之适用于铝合金温成形的热力本构描述。通过NAKAJIMA凸模胀形数值仿真及试验对比发现：高低温(25~400 ℃)相结合的软化型热拉伸本构方程可以准确地描述板料破裂前的集中软化特征，且可以有效满足6061铝合金高温成形性能的仿真需求。
关键字: 6061铝合金；温成形；热力拉伸；本构模型；数值仿真
（1. School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China;
2. School of Mechanical Engineering, Dalian University of Technology, Dalian 116024, China;
3. School of Automotive Engineering, Dalian University of Technology, Dalian 116024, China）
Abstract:Based on the dynamic recovery, dynamic recrystallization and deformation hardening characteristics of 6061-T6 aluminum alloy happened in the high temperature deformation process, the viscoplastic features at different temperatures were analyzed. The modified Field-Backofen model introduced with a softening factor was put forward to describe the thermal mechanics and constitutive model of aluminum alloy for hot forming. Combined with the experimental and simulation comparison research of NAKAJIMA test, the softening constitutive equation in the temperature range of 25-400 ℃ for hot forming is obtained and especially suitable for describing the behavior of sheet concentrate softening before crack, which is verified to be effective while applied to numerical simulation of forming process for 6061 aluminum alloy in hot forming.
Key words: 6061 Al alloy; hot forming; thermal tensile; constitutive model; numerical simulation
