不同应变率下泡沫铝的形变和力学性能

Deformation and mechanical property of aluminium foam at different strain rates

对低密度泡沫铝在不同变形率下的形变和力学性能进行了系统的试验研究。结果表明:(1)沿剪切方向骨架首先塌陷.即变形的局部化是低应变率下块体泡沫铝的主要变形特征;(2)在不同应变率下泡沫铝表现出体积应变基本上随工程应变呈线性变化,在低应变率下泊松比随轴向应变呈幂次关系增加,但在高应变率下泊松比随塑性应变增加.从一峰值降低并趋于稳定;(3)低应变率下泡沫铝材料塑性变形均匀.而高应变率下剪切变形较大;(4)泡沫铝材料的强度对应变率不很明显.但随塑性应变增加,它的率敏感性增加。

Deformation and mechanical property of aluminium foams with lower densities were experimentally studied at different strain rates. Results show as follows： （1） the deformation characteristic of Al foams at a lower strain rate presents an initial crushing down of the cell support along shear direction （localized deformation） ; （2） the volume strain of Al alloy foams varies linearly with the engineering strain, Poisson＇s ratio increases exponentially with strain at lower strain rates, but at higher strain rates, Poisson＇s ratio first decreases, then keeps about 0.1; （3） at lower strain rates, the deformation of AI alloy foams is more uniform than that at high strain rates, but at higher strain rates, there is greater shearing deformation accompanying the high strain-rate deformations; （4） Al foam shows lower strain-rate dependence at the room temperature when strain is below about 0. 4.