MEASUREMENT OF THE TEMPERATURE-FIELD INDUCED BY DYNAMIC CRACK-GROWTH IN BETA-C TITANIUM

The temperature increase at the tip of a dynamically propagating crack may have a significant effect on a material's mechanical properties, and hence on its dynamic fracture toughness. In order to start to unde rstand this phenomena, measurements of the temperature field at the ti p of a dynamically growing crack in Beta-C titanium alloy were perform ed using a linear array of high speed infrared detectors. The results show that a maximum temperature of 450-degrees-C is reached at the cra ck tip. In addition, the dynamic fracture toughness was measured for c rack speeds from 0 to 500 m/s. In this speed range, the toughness appe ars to be constant. Estimates of the crack tip energy release rate and plastic strain rate are made using analysis of the experimental data.