Further Development and Application of the Lithium Nuclear Microprobe for Hydrogen Analysis.
Final rept. 1 Mar 74-1 Jun 75,
GRUMMAN AEROSPACE CORP BETHPAGE N Y RESEARCH DEPT
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Experimental studies have demonstrated the unique capability of the Lithium Nuclear Microprobe for Hydrogen LNMH technique for the study of hydrogen-related mechanical property degradation and failure in metallic structural components, particularly those used in aerospace applications. This work has been a logical continuation of earlier studies, partially supported by NASC Contract N00019-72-C-0404, through which the LNMH was established as a reliable technique for accurate in situ measurement of localized hydrogen concentrations in material surface regions. Highlights of the present study include analyses of the effect of interfering background on hydrogen measurement sensitivities in different metals and alloys, development of techniques for areal mapping of hydrogen distributions, and probing to greater depths than previously achieved. The LNMH technique was also employed in the study of specific materials problems. Hydrogen concentrations were measured in the surfaces of copper-plated D6AC steel samples to evaluate the levels of hydrogen introduced during the various processing stages in the heat treatment of high strength steels. Especially significant among the applications has been the surface analysis of hydrogen as related to failure diagnostics of aircraft parts. This latter work has included the measurements of localized hydrogen in test fracture regions of nose landing gear axle socket assemblies Aerospace Materials Specification AMS 6407 steel and in fracture regions of service-failed and test-failed jet engine fan blades Ti-8Al-1Mo-1V. A number of analysis problems not previously encountered were found.
- Metallurgy and Metallography
- Nuclear Instrumentation