Eiji Matsushima

電磁超音波法による固体材料の熱拡散率と気孔率の研究 : 第2報,熱拡散率測定における誘導加熱分布の影響

Carbon-carbon composites are important structural materials for high-temperature environments. Their thermal properties and microscopic structures change with the temperature and the time required for heat treatment. It is expected that the thermal diffusivity and porosity will show different values at every moment during heat treatment. The objective of this study is to evaluate the time dependence of the thermal diffusivity and porosity simultaneously using the electromagnetic ultrasonic technique. This report describes the thermal diffusivity measurement of type 304 stainless steel and a two-dimensional weave carbon-carbon composite at room temperature, and the analyses of the eddy current and heat conduction to clarify the influence of the distribution of induction heating for thermal diffusivity measurement.

電磁超音波法による固体材料の熱拡散率と気孔率の研究 : 第1報,基本原理に関する実験および検討

Carbon-cabon composites are important structural materials at high temperature. Their thermal properties and microscopic structures change with the temperature and the time required for heat treatment. It is expected that the thermal diffusivity and porosity show different values at every moment during heat treatment. The objective of this study is to evaluate the time dependence of the thermal diffusivity and porosity simultaneously using the electromagnetic ultrasonic technique. This report describes the principles of measurement of the properties and the experiment to confirm the principles separately at room temperature. The longitudinal ultrasonic velocities of aluminum and carbon brick in the evaluation of porosity are 6350 m/s and 2530 m/s with precision of ±1.6% and ±0.4%, respectively. Is was confirmed that the aluminum and the carbon electrodes were able to be heated by the electromagnetic ultrasonic transducer. The thermal diffusivity of carbon brick measures 8-9 mm2/s but the accuracy of measurement will have to be investigated using the standard material in the future.