An experimental method for determination of dynamic mechanical behavior of materials at high temperatures

Abstract

An experimental method for measuring dynamic behavior of materials at high temperatures (up to 1600℃) was proposed in this work. The experimental system includes a classical split Hopkinson pressure bar, a MoSi2 heating source for achieving high temperature, and two piston rods added to complement the double-synchronous assembled system. During the experiments, the specimen can be supported by asbestos and semi-Alumina ceramic tube. To estimate the thermal conduction of the tested specimen during the cold contact time (CCT), the time during which the hot specimen is in contact with the cold bars before being compressed, the CCT was measured experimentally based on an on-off circuit, and the finite element method (FEM) was also employed to calculate the thermal conduction of the tested specimen. High speed camera was employed to record images of the specimen during testing through a window in the heating furnace. For better understanding of the influence of oxidation of specimens, the system was also equipped with an argon supply system to prevent the specimen from oxidation at the high temperatures. To verify the ability of the proposed method to operate at high temperatures, experiments were conducted on an TC4 alloy at test temperatures ranging from 20 to 1400℃ at the strain rate of 2000 s−1, and on SiC at temperatures ranging from 20 to 1600℃ at the strain rate of 250 s−1.