The influence of stress concentrators on the magnesium alloy mechanical behavior under deformation at high strain rates in the temperature range from 295 to 673 K

The paper presents the experimental results of the mechanical behavior of Mg-3% Al-1% Zn alloy at high strain rates at room and elevated temperatures. The flat samples with smooth working parts and notches with a radius of 10 mm, 5 mm and 2.5 mm were used. The experimental studies were carried out using the high-velocity servo hydraulic test machine Instron VHS 40 / 50-20. The samples were heated with flat ceramic infrared emitters on average from 60 seconds to 160 seconds. The temperature control in the working part of the samples was carried out in real time using a chromel-alumel thermocouple. Data on the stress triaxiality effect on the plastic flow stress and the strain to fracture of the magnesium alloy under tension with strain rates of 100 and 1000 1 / s at temperatures of 295 K, 473 K and 673 K were obtained. The stress triaxiality factor was varied within the range from 0.33 to 0.5. It was found that the value of tensile strain to fracture of the magnesium alloy decreased twice when the stress triaxiality factor increased from 0.33 to 0.5. This effect is realized in a wide range of strain rates and homologous temperatures T/Tm from 0.32 to 0.73 (Tm= 923 K is the melting point of Mg-3% Al - 1% Zn magnesium alloy). The obtained data were used for calibration of plastic deformation and fracture models which are used in computer-aided design of products from MA2-1magnesium alloy.