J. Phys. Colloques
Volume 43, Numéro C4, Décembre 1982
International Conference on Martensitic Transformations
Page(s) C4-791 - C4-796
International Conference on Martensitic Transformations

J. Phys. Colloques 43 (1982) C4-791-C4-796

DOI: 10.1051/jphyscol:19824129


R.A. Vandermeer

The University of Tennessee, Knoxville, TN 37916, U.S.A. and Union Carbide Corporation, Nuclear Division, Oak Ridge, TN 37830, U.S.A.

An important parameter for deciding whether or not a SME alloy is suitable for practical applications is the magnitude of the strain reversa1 accompanying martensite reversion. This research is concerned with elucidating metallurgical factors that cause degradation of this heat-activated recovery strain, ER. After explaining what is meant by degradation, two manifestations of degradation recently identified in near-monotectoid uranium-niobium alloys will be described. The first was associated with the onset of plastic deformation of the martensite beyond the reversible strain limit, EL ; a reduction of ER from 5.25% at 8% total strain, i.e. EL, to 2.9% at 12% total strain was observed. A second type of degradation depended strongly on the heating rate during reversion ; the ER for an imposed strain of 6.95% was reduced from a value of 5.25% to 1.3% when the heating rate was decreased from 40 deg/sec to 0.05 deg/sec. Degradation was attributed to a change in the transformation path and the interjection of time-dependent, low temperature aging reactions.