短纤维对泡沫铝压缩力学性能与吸能特性的影响研究

为探索闭孔泡沫铝加入短纤维后的力学性能和吸能特性变化规律。利用熔体发泡法在铝熔体中加入短碳纤维后制作得到纤维增强泡沫铝,通过万能材料试验机和高速液压伺服材料试验机在常温下分别对泡沫铝、纤维增强泡沫铝进行准静态和中应变率下(0.001~100 s-1)的动态力学性能测试,分析了纤维长度、纤维含量对泡沫铝力学性能和吸能特性变化规律。研究结果表明,纤维在泡沫铝内部主要呈现三种不同的形态模式:穿透模式、贯穿模式和嵌入模式;在平均孔径为2 mm的泡沫铝中加入长度为1 mm的纤维后,大多数纤维呈现穿透模式,泡沫铝整体性能下降,加入等含量长度为3 mm的纤维后,大多数纤维呈现贯穿和嵌入模式,平台应力和吸能效率有所提升;加入纤维后,泡沫铝整体呈现更为明显的应变率效应。

Effect of short fibers on compressive mechanical properties and energy absorption properties of aluminum foam

In order to explore the mechanical properties and energy absorption characteristics of closed cell aluminum foam after adding short fibers,a kind of fiber reinforced aluminum foam was prepared by adding short carbon fibers into molted aluminum by the melt foaming method.The dynamic mechanical properties of the aluminum foam and fiber reinforced aluminum foam at quasi-static and medium strain rates(0.001-100 s-1)were tested at room temperature by means of the universal material testing machine and the high speed hydraulic servo material testing machine.The mechanical properties and energy absorption characteristics of the aluminum foam with different fiber length and fiber content were analyzed.The results show that there are three different forms of fibers in aluminum foam:penetrating mode,penetration mode and embedding mode.Adding 1 mm fibers into the aluminum foam test piece with an average pore size of 2 mm,most of the fibers show penetrating mode,and the overall performance of the aluminum foam decreases.Adding 3 mm fibers,most fibers show penetration and embedding mode,and the platform stress and energy absorption efficiency increase.With the fiber,the aluminum foam presents more obvious strain rate effect.