Anomalous Effect of Strain Rate on the Tensile Elongation of Coarse-Grained Pure Iron with Grain Boundary Micro-Voids
The plastic deformation and damage behavior of coarse-grained commercially pure iron containing grain boundary micro-voids were investigated at room temperature with different strain rates ranging from 1.0×10-5s-1 to 1.0×10-2s-1 under uniaxial tension. It is found that, with increasing strain rate, the lower yield stress and ultimate tensile strength increase normally, and abnormally the elongation increases as well. By comparison with the similar cases of other materials, the present phenomenon of anomalous strain rate effect on elongation is thought to be related to the pre-existence of GB micro-voids in the raw CP iron material. The extending deformation of GB micro-voids towards the tensile direction would contribute more to the total elongation, as the strain rate increases; this should be the most possible reason for the anomalous strain-rate dependence of elongation.
X. M. Cao et al., "Anomalous Effect of Strain Rate on the Tensile Elongation of Coarse-Grained Pure Iron with Grain Boundary Micro-Voids", Advanced Materials Research, Vol. 214, pp. 334-338, 2011