Mechanism of IMCs in improving the compression property of Cu-Sn UPMs

Unidirectional Porous Materials (UPMs), characterized by their parallel unit cells aligning to the axis and high aspect ratios, exhibit remarkable thermal conductivity and superior energy absorption capabilities, rendering them ideally suited for applications as casings for reactive fragment. To mitigate the structural inhomogeneity of the unit cell prevalent in pure Cu UPMs fabricated by plastic deformation, a cold drawing method was employed to synthesize a uniformly structured Cu-Sn UPM. Sintering at 300 °C for 0.5 h effectively eliminated the interfacial disparities between Sn. Subsequently, the impact of heat treatment duration at 200 °C on the uniaxial compressive properties of the Cu-Sn UPM was examined. It was observed that heat treatment at this temperature can augment the densification strain of the UPM without diminishing its strength, consequently boosting its energy absorption capacity during the plateau phase. Specifically, a 16-h regimen at 200 °C resulted in a 20 % enhancement in densification strain and nearly a 30 % escalation in energy absorption. However, prolonging the heat treatment beyond 16 h attenuated the increments in densification strain and energy absorption significantly. This reduction is attributed to the thickening of the Cu₆Sn₅ and Cu₃Sn intermetallic compounds (IMCs) formed, which modified the compression-induced deformation mechanism of the cell walls.