TIME-DEPENDENT INTERNAL FRICTION IN ALUMINUM AND MAGNESIUM SINGLE CRYSTALS

Journal Article · Mon Feb 01 04:00:00 EST 1960 · Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRev.117.725· OSTI ID:4171903

Chambers, R H; Smoluchowski, R

Magnesium and aluminum single crystals subjected to varying amounts of oscillatory strain of audio frequency were investigated by measuring the complex modulus at audio frequencies as a function of temperature and time. If the amplitude of the applied excitation exceeds a critical breakaway strain, an excited mechanical state is shown in a modification of the amplitude dependence of the complex modulus. Upon cessation of the excitation, the excited state decays. The decay following short excitation times obeys a t/sup 1/3/ law, becoming a t/sup 2/3/ law as excitation approaches saturation. The short excitation decay rate is found to be governed by an activation energy in the range of 7 to 10 kcal per mole. The time dependence is considered to be caused by the dispersal and condensation of a pinning atmosphere which has high diffusivity and is easily dispersed by a dislocation segment undergoing pinning interactions with the atmosphere. (auth)

• Research Organization: Carnegie Inst. of Tech., Pittsburgh
• NSA Number: NSA-14-012114
• OSTI ID: 4171903
• Journal Information: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 117; ISSN PHRVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALUMINUM
ATMOSPHERE
DECAY
DEFORMATION
DIFFUSION
ENERGY
EXCITATION
FREQUENCY
FRICTION
MEASURED VALUES
MECHANICAL PROPERTIES
MONOCRYSTALS
PHYSICS
RADIO WAVES
TEMPERATURE