采用圆柱体试样,在Gleeble—1500热模拟实验机上进行高温高速压缩,对LF21铝合金在高温高速变形条件下的流动应力进行了实验研究.结果表明.LF21铝合金在变形温度250～450℃、变形速度15～45s~(-1)范围内.随变形速度增大,其流动应力增大;进入稳态流动后.随变形程度增大.其流动应力缓慢增大;并且.温度对流动应力的影响很强烈.对实验数据进行了回归处理,得出了LF21铝合金在稳态变形时流动应力的经验表达式. Cylindrical samples were used to carry out high-temperature and high-speed compression on a Gleeble-1500 thermal simulator to study the flow stress of LF21 aluminum alloy at high temperature and high speed deformation.The results show that when the deformation temperature of LF21 aluminum alloy is between 250 ℃ and 450 ℃ , Deformation rate of 15 ~ 45s ~ (-1) .With the deformation rate increases, the flow stress increases; into the steady flow, with the degree of deformation increases, the flow stress increases slowly; and temperature to flow The influence of stress is very strong.Experimental data are regressed and the empirical expression of LF21 aluminum alloy flow stress at steady state deformation is obtained.