Effect of Strain Rate and Relative Density on the Compressive Deformation of Open Cell Ti6Al Alloy Foam through P/M Route

Open cell Ti6Al alloy foams of varying porosity fractions have been made using ammonium bicarbonate as space holder through powder metallurgy route. In order to provide the sufficient strength in green compacts 2% of wt.% PVA solution was mixed with elemental metal powder and NH4(HCO3) particle prior to cold compaction. Green pallets were sintered at three stages at three different temperatures 600°C, 800°C and 1100°C. XRD and EDX analyses confirmed that no residue of space holder remained in the sintered foam samples. The compressive deformation behavior of Ti6Al alloy foams with varying relative densities was conducted under different strain rates (0.01, 0.1, and 1.0 s-1). The plateau stress, the Young’s modulus and the energy absorption of the foam increase with increase in the relative density following power law relationships. But the densification strain decreases with increases in relative density following a linear relationship. The strain rate sensitivity and the strain rate sensitivity parameter of these foams were also examined, and it was found that the strain rate sensitivity parameters were varying in the range 0.034 to 0.078.