Applied Research to Establish Infrared Detection Methods for Nondestructive Analysis of Metallic and Ceramic Structures, Part III

摘要

The feasibility study on thermal nondestructive evaluation of materials was continued. (See also AD-605 511) Various material properties or defects in samples were evaluated by one or both of two basic testing methods, known as the scan heat technique and the heat support technique. Both methods operate on the principle that heat transfer rates through a material are dependent on the properties of the material and the presence of internal defects. Heat is introduced at the surface of a sample. Its transfer away from the surface into the sample is gauged by continuous monitoring of surface temperature with an infrared radiometer. The scan heat technique utilizes a moving spot heat source, while the heat support technique relies on large area heating. Material parameters studied included voids and unbonds, adhesion of plating, cracks in coatings, bulk and surface deformation, grain size, and analysis of alloys. Several analytical solutions to the heat conduction equation were utilized for test parameter evaluation and the development of the heat support technique. (Author)