Electron Microscope Technique Suggested to Reveal Microstructures of Dispersion-Strengthened Materials
Abstract
This report describes a preparation and replication method which has produced consistently good results for a number of materials studied at the NASA Lewis Research Center. To show the effectiveness of the method evolved, measurements of volume percentages of dispersoids were compared with values obtained from chemical analysis. Typical microstructures of differently produced dispersion-strengthened materials are shown. The method that was found to be satisfactory uses conventional metallographic specimen preparation procedures up to the two final steps of polishing. For this final polishing, 3-micron and 1/2-micron diamond polishing compounds are necessary. This produces a flat and distortion-free surface. Etching of the samples should be extremely light. The etchants used depend on sample composition and history. The samples are then cleaned in an ultrasonic bath and further cleaned with plastic by dry stripping. Replication of samples with a conventional two-stage method of plastic-carbon and platinum shadowing follows. A good correlation was obtained between volume percent dispersoid measured on the resulting electron micrographs and the values obtained by chemical analysis. This replication procedure was found satisfactory for use with nickel, tungsten, chromium, cobalt, and their alloys. With suitable etchant changes, this replication procedure could also be applied to other dispersion-strengthened metals.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1968
- Accession Number
- ADA452994
Entities
People
- Bruno C. Buzek
Organizations
- National Aeronautics and Space Administration