Large deformation of magnesium sheet at room temperature by preform annealing part I: Uniaxial tension

Magnesium alloys do not generally show large formability at room temperature. This paper is part I of a study to utilize multi-step uniaxial stretching and annealing (MUSA) method to deform AZ31 magnesium alloy to large strains at room temperature. Mechanical properties of MUSA materials have been correlated to microstructural observations. Microstructure parameters such as grain size, twin fraction and textural changes arising from the different variants of MUSA process and their effect on work hardening behavior and cumulated room temperature elongation of AZ31 sheet are studied. Depending on the annealing conditions and pre-strains in different steps of the MUSA process, grain refinement or grain coarsening as well texture spreading was observed. The results indicate that a MUSA process can yield equivalent elongations in AZ31 sheet at room temperature to those attained at higher temperatures.