Microstructures and tensile properties of AZ31 magnesium alloy thin sheet
(College of Materials Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China)
Abstract: Microstructures, tensile properties, fracture characteristics of commercial AZ31 magnesium alloy thin sheet were studied by optical microscopy, scanning electron microscopy and uniaxial tensile test. Tensile tests were carried out at room temperature and 473K, with strain rates of 8.3×10 -44.2×10 -3s -1. The results show that grain refinement effects are better at high temperature, and it increases with the decrease of strain rate at 473K. Compared with that tested at room temperature, no apparent uniform plastic deformation stage exists in the stress—strain curves tested at 473K; afterwards, the stress—strain curve presents wavelike downward under condition of the small strain rate. Yield strength and tensile strength of the alloy decrease drastically while the elongation increases greatly. With the increase of strain rate, yield strength and tensile strength of the alloy increase, but the elongation decreases. The fracture of the alloy tested at room temperature is quasi-cleavage failure and ductile failure at 473K.
Key words: AZ31 magnesium alloy sheet； deformation； tensile properties