Titanium undergoes allotropic transformation from its α-phase (hexagonal close-packed (hcp) structure at temperatures less than 882.5 °C) to its β-phase (body centered cubic, bcc) structure at temperatures above 882.3 °C). Alpha-phase titanium products typically exhibit medium to high strength with excellent creep strength, whereas beta-phase titanium products typically exhibit very high strength and low ductility. Foams created under thermal cycling conditions have been shown to exhibit increased porosity due to the density difference between allotropic phases. Davis et al. produced titanium foams with 41% porosity (as compared to 27% porosity through the normal HIP creep mechanism). Increases in overall ductility were also observed in foams created through thermal cycling. In a similar experiment, porosity of 44% was achieved and determined as the maximum achievable porosity under thermal cycling conditions. A later study also utilized exploitation of transformation superplasticity conditions through HIP, but in this case, the titanium powder in the precursor matrix was replaced with titanium wires to create anisotropic pores. The resulting anisotropic pores showed closer correlation with natural bone in that the foams exhibited higher elastic moduli, yield strength and deformation when subjected to longitudinally loaded forces than when loads were applied transversely.