Route effects in I-ECAP of AZ31B magnesium alloy

An AZ31B wrought magnesium alloy was processed by incremental equal channel
angular pressing (I-ECAP) using routes A and BC. Despite the fact that the measured grain size for both routes was very similar, the mechanical properties were different. Tensile strength was improved using route A comparing to route BC, without ductility loss, while tension-compression anisotropy observed for route A was significantly suppressed when using route BC. Moreover, billet shape evolution resulting from subsequent passes of I-ECAP was studied. Significant distortion after processing using route BC and no occurrence of such effect for route A were observed. Results of a finite element analysis showed that non-uniform strain rate sensitivity might be responsible for different billet shapes. The conclusion is drawn that processing route has a strong influence on the billet shape and mechanical properties when processing magnesium alloys by I-ECAP.