Porous Cu foams with oriented pore structure by freeze casting

In this study, Cu foams with oriented pore structure were successfully prepared by freeze casting using Cu powders as the raw materials. The effect of cooling temperature on the microstructure and compressive stress were discussed. Results show that the pore size and porosity decrease with lowering the frozen temperatures. Furthermore, the Cu foam with pores parallel to the loading axis has larger compressive strength than that normal to the loading axis under the same strain. The 0.2% yield strength decreases from 25.4 to 12.6 MPa and 23.7 to 8.6 MPa, respectively in the direction parallel or normal to the freezing direction when the porosity increases from 65% to 80%.