Experimental study, on strain rate sensitivity of ductile porous irons

Experimental investigation on the behavior of porous irons under compression loading, especially at high strain rate compression loading, is carried out in this study to help understanding the effects of strain rate and porosity on the yield strength, energy absorption and load carrying capacity of this group of porous metals. Samples of porous iron with porosity ranging from 10% to 35% were fabricated by the powder metallurgy technology. The tests were conducted at a wide range of strain rates from 10−3 to 103/s using a servo-hydraulic machine and a split Hopkinson pressure bar (SHPB) system. It has been found from the results that the material shows a bi-linear behavior over the tested strain rates. The porosity has a direct effect on the yield strength and post yield behavior of the material, while the yield strength, load carrying capacity and energy absorption capability of porous irons vary with the strain rate. Findings are being used to develop a phenomenological constitutive model for porous irons.