RESISTANCE MATERIALS FOR HIGH‐TEMPERATURE STRAIN MEASUREMENT

The performance of some commercially available base and noble metal resistance alloys usable as strain sensors in high temperature strain gauges is experimentally assessed with emphasis on the determination of post yield strain under these conditions. In order for Cu‐Ni resistance alloys to be used satisfactorily at 600 deg.C, gross surface oxidation must be prevented by an argon shield and the surface of the sensor must be pre oxidised to inhibit grain boundary attack from partial pressure of oxygen in the argon atmosphere.