Fabrication of Highly Porous CuAl Intermetallic by Thermal Explosion Using NaCl Space Holder

Abstract

A high-porosity CuAl-based intermetallic compound with composition Cu-50 at.% Al has been successfully prepared by thermal explosion (TE) using NaCl as space holder. The results showed that the NaCl particles were completely removed from the green compact by water leaching. The temperature of the specimen during the TE and the evolution of the porous microstructure were investigated. The TE was ignited at 560°C, and the specimen temperature increased to 775°C in 3 s, resulting in formation of intermetallic CuAl and CuAl2 phases in the final product. A porous CuAl-based intermetallic compound with up to 62 vol.% open porosity was produced when adding 60 vol.% NaCl. The compound exhibited a bimodal pore size structure, including large pores (200 μm to 300 μm) that replicated the NaCl particles and small pores (5 μm to 10 μm) interspersed in the pore walls. Moreover, the large pores were interconnected by channels and formed an open CuAl-based intermetallic cellular structure, having great potential for use in heat exchange and filtration applications.