Mechanical Behavior of Magnesium Alloy AZ61 at Different Strain Rates and Temperatures under Tensile, Compressive, and Flexural Loads

An experimental investigation on the mechanical properties of AZ61 magnesium alloy is presented under tensile, compressive, and flexural loads. Quasi-static experiments under tension and compression are performed at strain rates of $0.0001–0.1{\mathrm{s}}^{-1}$, while flexural (three-point bending) tests are conducted at cross-head speeds $1–100\mathrm{mm}/\min$ for different span lengths (80–160 mm) and orientations (flat and transverse) of flexure specimens at room temperature 25°C. Experiments at 100°C, 150°C, and 200°C are carried out under tension. The heating rate and soaking time of the specimens are $8°\mathrm{C}/\min$ and 15 min, respectively. Dynamic tests on tension ($700–\mathrm{1,150}{\mathrm{s}}^{-1}$) and compression ($\mathrm{1,600}–\mathrm{4,000}{\mathrm{s}}^{-1}$) are performed at room temperature. It is found that the alloy is positively sensitive to tensile, compressive, and flexural loads and negatively sensitive to thermal loads. The effects of specimen geometry are observed on the compressive properties of the alloy. The mechanisms of material failure are studied by scanning electron microscope (SEM), and it is found that the propensity of dimple pattern fracture increases with increasing temperature. Also, the suitability of the existing Cowper-Symonds and Johnson-Cook models are discussed in connection with the aforementioned loading conditions.