胞状AlCu5Mn合金泡沫的压缩性能和能量吸收特性

摘要

用熔体发泡法制备孔隙率为51.5%～90.5%、孔结构均匀的胞状铝合金(AlCu5Mn),研究其孔结构、压缩性能、能量吸收能力、能量吸收效率和吸能性能.结果表明:胞状铝合金孔结构由高孔隙率(88.8%)时的大孔径、多边形孔向低孔隙率(62.5%)时的小孔径、球形孔孔结构过渡,其压缩应力(σ)-应变(ε)曲线具有线性变形阶段、屈服平台阶段和致密化阶段三个部分,由线性变形阶段进入屈服平台阶段所对应的ε_s值介于2%～9%之间;屈服强度σ_s~*随着孔隙率的增大而下降,在孔隙率相同的条件下,胞状铝合金的力学性能优于胞状铝和多孔铝合金,其比刚度高于钢;当应变为定值时,胞状铝合金单位体积和单位质量的压缩吸能能力(C和C_m)都随着孔隙率的升高而降低,但是孔隙率在73.5%～82.1%范围内时,其C_m与ε的关系几乎不随孔隙率的改变而改变;对于孔隙率为51.5%～90.5%的胞状铝合金,它们的吸能效率的峰值都大于80%.胞状铝合金的C-σ和C_m-σ关系可以表征其吸能性能,从而可以根据实际工况选择作为减振吸能材料的胞状铝合金的最佳孔结构.%Cellular Al alloy (AlCu5Mn) foams with wide porosity range (51.5%-90.5%) and homogeneous pore structures were fabricated successfully by melting foaming method. The pore structure, compressive property, energy absorption capacity, energy absorption efficiency and the judgment of energy absorption property were investigated. The results show that the pore structure varies from large diameter and polygonal pores for high porosity (88.8%) samples to small diameter and globular pores for low porosity (62.5%) samples. A typical compressive stress(σ)-strain(ε) curve consists of three parts (linear deformation stage, yielding plateau stage and densification stage). The ε_s values at yielding points are within the range of 2%-9%, and the value of yielding stress σ_s~* decreases with increasing porosity. For a given porosity, the compressive properties are better than those of cellular Al and other Al based foams, and the specific stiffness are higher than those of steel. Both energy absorption capacity per unit volume C and per unit mass C_m decrease with increasing porosity, but the C_m-ε curves for cellular AlCu5Mn foams with porosity of 73.5%-82.1% almost do not alter with increasing porosity. The peak values of the energy absorption efficiencies of cellular AlCu5Mn foams with porosity of 51.5%-90.5% are all greater than 80%. The relationships of C-σ curves and C_m-σ curves can be used to characterize the energy absorption properties, which imply that they can be used as a criterion to choose the pore structure of cellular AlCu5Mn foam as energy absorption material in application.