Non-destructive characterization of carbon fiber composite/Cu joints for nuclear fusion applications

Several non-destructive testing methods, lock-in thermography, ultrasonic inspection, microtomography and microradiography, were used to assess the manufacturing quality of joints between carbon fiber reinforced carbon composites and Cu/CuCrZr.The results revealed that ultrasonic inspection is critical since carbon composites and copper have a significant difference in the acoustic impedance; moreover this technique is sensitive to irregular shaped joined surfaces; microtomography and microradiography offer qualitative information on the joint, since carbon is significantly less X-rays sensitive than copper. Lock-in thermography gives information on thermal continuity at interface. Non-destructive test results have been validated by destructive tests (morphological analysis and mechanical testing).