Large elongations in WE54 magnesium alloy by solute-drag creep controlling the deformation behavior

Solute-drag creep is a diffusion-controlled process that may govern deformation in coarse-grained materials with solute atoms in solution. Elongation-to-failure tensile tests were conducted in a WE54 alloy containing solutes of Y and Nd in the range 25-450 degrees C. Elongations of more than 150% were observed at high temperatures and a maximum elongation to failure of 312% was determined at 450 degrees C and 10(-2) s(-1). Microstructural observations show elongated grains and the presence of dislocation bands after deformation under these conditions. Strain-rate-change tests reveal a range at high temperatures showing low stress exponents. Since grain boundary sliding was discarded as a possible controlling mechanism, the observed low stress exponents, high elongations and elongated grains are attributed to solute-drag creep as the principal deformation mechanism.