The role of microstructure and texture in controlling mechanical properties of AZ31B magnesium alloy processed by I-ECAP

Mechanical properties of AZ31B magnesium alloy were modified in this work by various processing routes of incremental equal channel angular pressing (I-ECAP) followed by heat treatment. Possible strategies for improving ductility and strength of the alloy were investigated. Processing by routes A and BC showed that texture plays predominant role in controlling mechanical properties at room temperature. Four passes of I-ECAP by route C followed by annealing enhanced ductility up to 0.35 of true strain. It was found that tensile twinning was important in accommodating strain during tensile testing, which resulted in a very good hardening behaviour. The yield strength was improved to 300MPa by refining grain size to 0.8µm in I-ECAP at 150°C. The obtained structure and properties were shown to be stable up to 150°C. True strain at fracture was increased to 0.2 after annealing at 150°C without lowering strength.