Diagnostic technique for degradation of engineering materials by measurement of thermophysical properties

✍ Scribed by Kazunori Kato; Ichiro Takahashi

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 608 KB
• Volume: 36
• Category: Article
• ISSN: 1099-2871
• DOI: 10.1002/htj.20178

✦ Synopsis

Abstract

The thermal conductivity of the surface layer of engineering materials changes in the early stages of material degradation due to the appearance of micro‐cracks. A new method for evaluating and assessing the degree of degradation of a material using this change is proposed herein. The influence of the micro‐cracked layer on the temperature response as measured by a thermophysical handy tester was theoretically examined. By defining a thermal degradation parameter, the amount of degradation of various materials was evaluated. In order to verify this theory, fatigue tests using metallic materials were conducted. Comparisons before and after the fatigue tests were then made to establish the correlation between the density of micro‐cracks and the decrease in thermal conductivity. As a result, it was ascertained that a thermal degradation parameter can easily be estimated from a temperature response curve obtained using the tester. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(8): 501–512, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20178