Dynamic mechanical properties and constitutive relationship of fine-grained Al/Fe composite materials with rich aluminium

Split Hopkinson bar was used to study the dynamic mechanical properties of fine-grained aluminium-rich Al/Fe composite materials obtained by hot-pressing sintering, and the true stress-strain curves were acquired under different strain rates (100~2300 s^-1), which were compared with the properties under quasi-static situation (0.01 s^-1). The results reveal that the strength of materials improves and the plasticity decreases with the increase of strain rate. The yield strength and elastic modulus under strain rate of 2300 s^-1 is 7.8 and 2.3 times, respectively, higher than that under the quasi-static situation. The fracture morphology has been analyzed. It is indicated that the fracture mode consists of cleavage fracture, intergranular fracture and dimple fracture. According to experimental data, a modified dimensional elastic and brittle constitutive model with damage was built, which obtained the constitutive equation before the fracture failure of specimens and the relationship between parameters and strain rate. The modified constitutive model is presented to fit the experimental data very well.