Anisotropic Compressive Behavior of Metallic Foams under Extreme Temperature Conditions

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.

Cryogenic Drilling of AZ31 Magnesium Syntactic Foams

“…It is seen that cryogenic cooling (180 N) increases the thrust forces by 45% and 16% compared to wet machining (125 N) and dry machining (155 N) conditions, respectively. Reduction in cooling temperature to subzero conditions causes an increase in strength of the workpiece material and, hence, higher thrust force, and agrees with the reported literature [ 9 , 25 , 26 ]. Sudden cooling could promote the hardening of the magnesium matrix and enhance its brittleness.…”

“…The ceramic alumina microsphere cracking is also affected due to the rapid cooling process [ 10 ]. It has been highlighted in the literature that material yield strength and hardness of the closed cell syntactic foam increases as testing temperature decreases [ 8 , 9 ]. Experimental results indicate a transformation in the plastic deformation behavior of the workpiece material with a change in the cooling method in the form of variation in the magnitude of machining forces.…”

“…The corrosion behavior of magnesium-based alloys is controlled through the modification of their surface characteristics through enhanced coating compositions, the choice of machining methods, and various mechanical working methods [6]. It has been shown that an increase in the volume fraction of hollow microspheres increases the hardness, compression yield strength, peak compression strength, and plateau strength of the syntactic metal foams [7][8][9][10]. The coarser the average size of hollow reinforcements is, the lower the hardness of the magnesium closed-cell foam [11,12].…”

Manufacturing Technologies of Carbon/Glass Fiber-Reinforced Polymer Composites and Their Properties: A Review

“…Aluminum alloys are widely used in the aerospace industry for different structural applications [130,131]. Nevertheless, depending on the type of used fibers, the Fiber-Reinforced Polymer (FRP) composites can have a stiffness/weight ratio up to 5 times, while the damping properties exceed 100 times, compared to the aluminum alloys.…”

Correlation Modeling between Morphology and Compression Behavior of Closed-Cell Al Foams Based on X-ray Computed Tomography Observations

“…Examining whether a cellular structure is geometrically anisotropic is a critical issue [49]. In this respect, it is known that the effects of the structural anisotropy can be considered by performing compressive tests under different loading directions [50]. This peculiarity of the proposed model does not really differ from the behavior of the type of cellular structures examined here, which are obtained by a highly directional foaming process [51].…”