Young's modulus of polycrystalline Nb/sub 3/Sn between 4. 2 and 300 K

Journal Article · Thu Jan 31 23:00:00 EST 1980 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.327730· OSTI ID:5563364

Bussiere, J F; Welch, D O; Suenaga, M

Ultrasonic measurements show that the shear modulus 1/2 (C/sub 11/-C/sub 12/) softens dramatically as single crystals of Nb/sub 3/Sn approach the martensitic transition near 50 K. It is expected that Young's modulus of polycrystals will also soften, but previous ultrasonic measurements, which suffer from severe damping, fail to show the expected effect. We have measured Young's Modulus of polycrystalline Nb/sub 3/Sn between 4.2 and 300 K by static beam-deflection methods and observe marked softening. A value of 1.32 x 10/sup 12/ dyn cm/sup -2/ was obtained at 300 K by the deflection of thin Nb/sub 3/Sn-Nb-Nb/sub 3/Sn composite strips by external stress. The variation of the modulus with T was obtained from the change in the radius of curvature of internally stressed Nb/sub 3/Sn-Nb composite strips. (This method is made possible by the near-perfect match between the thermal expansion coefficients of Nb and Nb/sub 3/Sn.) The modulus is found to be proportional to lnT between 50 and 300 K and is temperature independent below the superconducting T/sub c/, resulting in a decrease by a factor of approx.2 between 300 and 18 K. The observed softening is somewhat less than that predicted by a polycrystalline average of the experimental single-crystal elastic constants,but is much larger than that observed with ultrasonic measurements.

• Research Organization: Brookhaven National Laboratory, Upton, New York 11973
• OSTI ID: 5563364
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 51:2; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ACOUSTIC TESTING
ALLOYS
CARBON ADDITIONS
CRYSTALS
ELASTICITY
IRON ALLOYS
LOW TEMPERATURE
MARTENSITE
MATERIALS TESTING
MECHANICAL PROPERTIES
MEDIUM TEMPERATURE
MONOCRYSTALS
NIOBIUM COMPOUNDS
NONDESTRUCTIVE TESTING
POLYCRYSTALS
SHEAR PROPERTIES
TENSILE PROPERTIES
TESTING
TIN COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
ULTRALOW TEMPERATURE
ULTRASONIC TESTING
VERY LOW TEMPERATURE
YOUNG MODULUS