Highest strength for 7075 Al alloy was obtained by combining the equal-channel-angular pressing (ECAP) and natural aging processes. The tensile yield strength and ultimate strength of the ECAP processed and naturally aged sample were 103% and 35% higher, respectively, than those of the coarse-grained 7075 Al alloy counterpart. The enhanced strength resulted from high densities of Guinier–Preston (G-P) zones and dislocations. This study shows that severe plastic deformation has the potential to significantly enhance the mechanical properties of precipitate hardening 7000 series Al alloys.

Severe plastic deformation (SPD), for example by intense plastic straining under high pressure, is an innovative technique for producing ultrafine-grained (UFG) metals and alloys. The SPD fabricated UFG structures can lead to enhanced superplasticity, which, however, depends strongly on processing parameters. The present paper focuses on examples of attaining enhanced superplasticity in several alloys, subjected to SPD and considers the relationship between processing – UFG structures – superplastic properties in SPD produced materials.

The progress of high temperature deformation in samples of two commercial titanium alloys with superplastic (SP) structure, non-SP structure, and with an SP layer sandwiched between the non-SP regions has been studied on the scale of the entire deformed volume and on the scale of grain groups. The results of mechanical behavior showed that samples with SP layer exhibit higher stress level than those with completely SP structure and higher strain rate sensitivity than those with completely non-SP structure. Samples with SP layer demonstrate a more pronounced deccrease in strain rate sensitivity with the increase of strain than samples with completely SP structure. Deformation in the SP layer proceeds as grain shear in a layer-by-layer manner. The deformation of SP layer through the operation of cooperative grain boundary sliding, i.e., sliding of grain groups as an entity along certain grain boundary surfaces, provides the main contribution to the total strain.