Strength and failure of ultrafine grain and bimodal Al-Mg alloy at high temperatures

Abstract

Uniaxial tensile tests are conducted at room and high temperatures on a bimodal grain size Al-Mg alloy with an ultrafine grain matrix as the major constituent to evaluate the strength and failure mode of the material. The coarse grain ratio and anisotropy effects are also investigated as parameters that could influence the mechanical behavior. It was found that the strength of the material decreases rapidly with temperature such that at 473 K, it was somewhat weaker than a comparable conventional alloy. Dynamic recovery was observed and found to be dependent on coarse grain ratio. Strength anisotropy was found to be reduced with increasing temperature. No evidence of thermally or mechanically assisted grain growth were observed.