Non-contact mechanical property measurements at ultrahigh temperatures

The “Electro-Magnetic Mechanical Apparatus”, a novel non-contact method of mechanical testing of ultrahigh temperature ceramics at high temperatures, was developed where a mechanical stress is applied using Lorenz forces on a sample heated to high temperatures with an electric current. The design of the apparatus and an analysis relating stress to magnetic flux density, electrical current, and specimen dimensions are presented here. Significant creep deformations were observed in ZrB2–SiC samples deformed under 20 MPa of flexural stress resulting in 0.08% strain after 240 s at 1600 °C and 0.21% strain after 150 s at 1750 °C. A fatigue load of 6 MPa at 60 Hz frequency at 1700 °C in air increased the oxidation rate. This mechanical apparatus has potential application not only for high temperature creep and fatigue experiments but also fracture and elasticity. Though developed for ceramics, this technique can be used to study high temperature mechanical properties of any conducting material.