Dynamic response of severe plastic deformation processed 1070 aluminum at various temperatures

The properties of materials are directly related to their microstructure, one quantitative measure of which is the average grain size. Most of the strength properties of crystalline materials are improved with diminishing grain size, and therefore new technologies have been developed to produce also bulk metals with nanocrystalline or ultrafine grain sizes. In this paper, we report the results of compression experiments on ultrafine-grained 1070 aluminum produced by different routes of equal-channel angular pressing (ECAP). The compression tests were conducted at different strain rates and temperatures using a servo-hydraulic materials testing machine and the Split Hopkinson Pressure bar technique. The results show that both increasing strain rate and decreasing temperature increase the work hardening capability of ultrafine-grained aluminum, thus enhancing the ductility of the material. The strain rate dependence of ultrafine-grained aluminum is also higher than that of the coarse-grained material, which implies that there are also differences in the active deformation mechanisms of these two different types of materials.