Strain rate sensitivity and energy absorption of Zn–22Al foams

Effects of Heat Treatment on Compressive Behavior and Energy Absorption Characteristic of ZA22 Foams

“…This result is similar to ZA22 foams fabricated by powder metallurgical process. [10] Compared with as-fabricated foams, the strain ranges of heat-treated foams in the plateau region didn't change, the compression strengths (defined as upper yield point in curve) were totally more than 1 MPa and obviously higher than those of as-fabricated foams, and the plateau stress fluctuated notably which implied that the brittleness of heat-treated foams increased.…”

“…In this work, e D was determined as the intersection of the tangents to the plateau region and densification region using the method suggested by Paul et al [22] This method is commonly used for estimating energy absorption capacity in some references. [8,10,21,22] The energy absorption capacities of as-fabricated and heattreated foams with different relative densities are shown in Figure 5. It can be found that the energy absorption capacities of foams before and after heat treatment increased with increasing relative density.…”

“…Heat treatment is considered as an effective means because it improves the compressive behavior and the energy absorption characteristic of metallic foams by altering the microstructure and property of cell wall metal. [2,[5][6][7][8][9][10][11][12][13] The heat treatment procedure for metallic foams is usually derived from the corresponding bulk metal. However, the effects of the heat treatment on the microstructure and property of metallic foams are different from that of bulk metal, because the low thermal conductivity and heterogeneous structure of metallic foams can result in insufficient quenching rate and thermal stress localization.…”

“…Consequently, Zn-Al eutectoid alloy foams show a higher energy absorption capacity than Alporas foams when strain rate increases. [10] Additionally, ZA22 eutectoid alloy possesses preferable damping property arising from the phase boundary between Al-rich phase and Zn-rich phase. [14,15] The damping property of closed-cell Zn-Al eutectoid alloy foams is slightly higher than that of the bulk alloy owing to introducing a mass of macroscopic pores.…”

Metal Foaming Studied In Situ by Energy Dispersive X‐Ray Diffraction of Synchrotron Radiation, X‐Ray Radioscopy, and Optical Expandometry

“…[2][3][4][5][6] Pressing powder mixtures under vacuum or reducing the melting temperature by alloying Al with Si, Cu, Mg, Zn, or combinations of these elements are also successful strategies for producing foams of improved pore structure and properties. [7][8][9][10][11][12][13][14] However, the more alloyed Al is, the more complex is to predict how the decomposition of TiH 2 will be inside expanding foams.The correlation between regimes of H 2 release and phase transformations of both as-received TiH 2 and pre-oxidized TiH 2Àx powders under flowing Ar were recently clarified, by using a combination of in situ diffraction methods, thermoanalysis and electron microscopy that helped to develop core shell models to describe the decomposition of the hydride in both conditions. [15] However, studies on H 2 desorption from foamable precursor material made for example by the powder metallurgical route, show different behavior than the one from loose powders, [16,4,9] which suggests that the phase transformations of TiH 2 during foaming of Al-based alloys might be different.…”