ポーラスアルミニウムの圧縮特性に及ぼす合金組成およびスキン層の影響

Abstract

Porous aluminum alloys prepared by a precursor method inherently develop a thin solid layer, also known as the skin layer, on their surface. Formation of a skin layer is a characteristic feature of the precursor method, and it affects certain compressive properties of the alloy. Furthermore, investigating the effect of changes in the aluminum alloy composition on the compressive properties is important. In this study, the effects of the skin layer on several compressive properties were investigated for two different porous aluminum alloys developed by the precursor method: AA6061 and Al–7mass% Si. The plateau stress and energy absorption of both alloys increased with increasing bulk density, irrespective of whether the skin layer was present or not. In the case of the porous AA6061 alloy, the skin layer did not affect the plateau stress; however, the plateau strain increased under large deformation because the skin layer peeled off under relatively small deformations in the compression test, causing a decrease in the relative density of the specimen. In the case of the Al–7%Si alloy, the skin layer affected stress oscillation and the plateau stress became unstable. Peeling of the skin layer also increased the plateau strain, resulting in increased energy absorption.