Electrical Conductivity Evaluation Techniques for Superalloy Single-Crystal Steel

Superalloy single-crystal steel grade is a material for high-temperature gas turbine parts and is essential for preventing explosion accidents caused by high temperature and heat. To establish an infrastructure and a database for the characterization of gas turbine core materials, tests for thermal, mechanical, and electrical properties are required. The required thermal property tests include thermal conductivity, specific heat, and thermal expansion coefficient tests. The mechanical tests include tensile tests at room and high temperature and fatigue tests. The electrical tests include conductivity tests; also, in this study, various measurement methods were used to compare and evaluate the reliability of the evaluation results for the conductivity test. The conductivity was compared and evaluated using five methods, namely, the four-terminal, direct current comparator resistance bridge, four-point probe, van der Pauw, and eddy current. The conductivity obtained was 1.210% International Annealed Copper Standard (IACS), and the measured values for the five methods agreed with each other within 0.1% or less, with a measurement uncertainty of about 0.2% to 0.6% or less within a 95% confidence level.