A RADIANT HEATING METHOD FOR PERFORMING HIGH-TEMPERATURE HIGH-STRAIN-RATE TESTS

A radiant heating system is described which is capable of raising the temperature of a test specimen to 800 degrees C in approximately 10 s, while the apparatus remains at room temperature. The system uses two infrared lamps which are controlled with an electronic timer to within a resolution of 0.1 s. The radiant heaters reach 90% of their maximum power in approximately 3 s. The radiant heating system has been used to heat tensile specimens prior to impact loading using the tensile sp lit-Hopkinson pressure bar. Impact tensile tests at a nominal strain r ate of 2500 s(-1) and initial temperatures of 20, 200, 400 and 600 deg rees C were performed on the titanium alloy 90% Ti-6% Al-4% V. A sharp reduction in yield stress and an increase in elongation at fracture w ere noted in the high-temperature tests. The implicit finite element c ode ABAQUS has been used to model the radiant heating and thermal diff usion in the tensile specimen and loading bars. The modelling has been used to determine the thermal distribution in the test specimen prior to loading and the validity of the calibration technique.