Processing and compression testing of Ti6Al4V foams for biomedical applications

Open cell Ti6Al4V foams (60% porosity) were prepared at sintering temperatures between 1,200 and 1,350 A degrees C using ammonium bicarbonate particles (315-500 mu m) as space holder. The resulting cellular structure of the foams showed bimodal pore size distribution, comprising macropores (300-500 mu m) and micropores (1-30 mu m). Compression tests have shown that increasing sintering temperature increased the elastic modulus, yield and compressive strength, and failure strain of foams. The improvements in the mechanical properties of foams prepared using smaller size Ti64 powder with bimodal particle distribution were attributed to the increased number of sintering necks and contact areas between the particles. Finally, the strength of foams sintered at 1,350 A degrees C was found to satisfy the strength requirement for cancellous bone replacement.