Anisotropic Compressive Behavior of Metallic Foams under Extreme Temperature Conditions.

Omid Khezrzadeh,Emanoil Linul,Omid Mirzaee,Esmaeil Emadoddin

doi:10.3390/ma13102329

Abstract

Metallic foams find their applicability in complex systems that operate under both real-life conditions (Earth living conditions) and extreme temperature conditions (low or high temperatures). In this paper, the main mechanical properties of closed-cell aluminum alloy (A356) foams under quasi-static compression loading conditions were determined. In order to investigate the compressive behavior, three orthogonal directions (X, Y, and Z) and three testing temperatures (−196, 25 and 250 °C) were considered. It has been observed that the temperature significantly influences the strength properties and energy absorption performances of the aluminum metallic foams AMFs. Moreover, it was found that microstructural characteristics, such as intrinsic defects (intracellular cavities, micro-pores and thin cell-walls) and structural anisotropy (shape, size and orientation of cells), play a decisive role in the mechanical behavior of AMFs. Moreover, the paper compares the relative percentage change (relative percentage increase and decrease) of the main normalized compressive properties (yield stress, plateau stress, densification stress and the energy absorption) of AMF samples, according to testing temperature and loading direction.

Highlights

In recent years, metallic foams (MF)s have been used in many engineering fields as lightweight and protective structures due to their high strength properties and outstanding energy absorption capabilities [1,2,3]
The aluminum alloy A356 was melted in a stainless steel mold at 700 ◦ C, while, in order to increase its viscosity, 2 wt.% calcium granule was added to the melted aluminum
aluminum metal foams (AMFs) samples werecurves subjected to aobtained compression of about strain,4having corresponding energy were andtest showed in80%

Summary

Introduction

Metallic foams (MF)s have been used in many engineering fields as lightweight and protective structures due to their high strength properties and outstanding energy absorption capabilities [1,2,3]. Due to the advantageous collapse mechanisms of the cell structure, in recent years, aluminum metallic foams AMFs have received more attention than fully dense metal materials (e.g., steel, aluminum, etc.). AMFs, similar to most of polymeric foams, are anisotropic, which can be manufactured in different ways to obtain structure (geometry) anisotropy or material (mechanical property) anisotropy [10,11,12]. Cell geometries, such as cell size and cell morphology, affect the mechanical behavior of porous/cellular materials [13,14,15]. It was found that the main mechanical properties of cellular materials significantly vary with the number of cells or the size of the constituents [16,17,18,19,20,21,22,23]

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