Accession Number : ADD018611
Title : High Temperature Shape Memory Effect in Ruthenium Alloys.
Descriptive Note : Patent Application, Filed 10 Sep 97
Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC
Personal Author(s) : Fonda, Richard ; Vandermeer, Roy ; Jones, Harry
PDF Url : ADD018611
Report Date : Sep 1997
Pagination or Media Count : 29
Abstract : The shape memory effect is observed in alloys which undergo a thermoelastic martensitic transformation. This transformation is characterized by the continuous growth of martensite plates as the temperature is lowered and, comparably, the continuous disappearance of these martensite plates as the temperature is subsequently raised. The reversible nature of this transformation can lead to the many interesting features of the shape memory effect. One effect is superelasticity, which occurs above the transformation temperature and consists of the activation of the martensitic transformation in response to an external stress. Any shape changes produced during the transformation are reversed upon release of the external stress. Below the transformation temperature, the material can exhibit a one way or two-way shape memory effect The one-way shape memory effect exists when the material is deformed below the martensitic transformation temperature and then reverts to its original shape upon heating to above the transformation temperature. With appropriate mechanical and thermal training of the material this effect can be modified into a two-way shape memory effect. This two way effect is a reversible shape change which results during both heating and cooling the material through the transformation temperature range.
Descriptors : *PATENT APPLICATIONS, *MEMORY DEVICES, *RUTHENIUM ALLOYS, STRESSES, THERMAL PROPERTIES, TEMPERATURE, MECHANICAL PROPERTIES, ACTIVATION, TRAINING, MODIFICATION, GROWTH(GENERAL), SHAPE, ELASTIC PROPERTIES, ALLOYS, COOLING, PLATES, REVERSIBLE, EXTERNAL, RANGE(EXTREMES), TRANSFORMATIONS, MARTENSITE, THERMOELASTICITY
Subject Categories : Metallurgy and Metallography
Computer Programming and Software
Distribution Statement : APPROVED FOR PUBLIC RELEASE