Mechanical Behavior of 97.2% W Alloy in Tension at High Temperatures

The objective was to investigate the behavior of 97.2 tungsten alloy in tension. A modified button head specimen was heated using resistive heating techniques. The affect high temperatures, medium strain rates, and heating rates had on the stress-strain results were observed. A high speed optical pyrometer and an optical clip gage were utilized for temperature and strain measurements. The optical clip gage could measure strain at strain rates up to 11.8s. The room temperature experiments were at strain rates of 10-exp 4s, 10-exp 2s, and 5s. The high heating rate experiments were at temperatures of 727 deg C, and 1097 deg C, heating rates of 5.4 deg Csec and 536 deg Csec and a strain rate of 5s. Increase in yield point and flow stress were observed as the heating rate was increased. A modified Johnson-Cook MJC material model was proposed to include the effect of heating rate. The constants in the MJC model were determined based on the experimental results. Tungsten, High temperatures, Strain rate, Material modeling.