Damping Degradation in Incramute and Sonoston due to Low Temperature Storage
Abstract
Two commercial manganese copper based alloys, SONOSTON and INCRAMUTE, were evaluated for their ability to maintain optimum damping capacity with time when stored at room temperature and 100 C, which represents a temperature range within which marine equipment commonly operate. Damping measurements were obtained using the modified resonant dwell technique. Significant degradation occurs within 12 days in both alloys when stored at room temperature or 100 C, although SONOSTON stored at 100 C exhibited stable damping in the active strain range. Recovery treatments at 125 C indicated that a recovery mechanism was operative in INCRAMUTE, but absent in SONOSTON. In fact a 125 C recovery treatment actually appeared to degrade damping in the active strain range in SONOSTON. X-ray diffraction results indicated that the changing damping characteristics were related to lattice changes detectable by that technique. Transmission electron microscopy revealed an unique contour jumping phenomena with electron beam heating, which is hypothesized to indicate a sensitive elastic transformation, with a low strain threshold, of the tweed microstructure. In addition, although not quantitatively evaluated, a modulus dicontinuity with time was observed upon initially vibrating cantilevers beam specimens, possibly related to the necessity the damping mechanism of the tweed microstructure.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1986
- Accession Number
- ADA177390
Entities
People
- Lewis W. Leary
Organizations
- Naval Postgraduate School