Applications of microdynamics and lattice mechanics to problems in plastic flow and fracture. Progress report, January 1, 1973--December 31, 1973

Technical Report · Mon Jan 01 00:00:00 EST 1973

DOI:https://doi.org/10.2172/4386037· OSTI ID:4386037

Bilello, J C

Dislocation motion in the initial stages of plastic flow for asgrown and ultrahigh-vacuum-outgassed tungsten single crystals was studied by a low- frequency microstrain technique over the temperature range from 4.2 to 300 deg K. In terms of the observed elastic limit, anelastic limit, and the fractional energy dissipation, the effects of purity, temperature, and stress amplitude on the frictional stress for dislocation motion are discussed. In the highfrequency regime, ultrasonic attenuation measurements in copper and copper-- nickel alloys reveal a linear dependence of the velocity-dependent damping coefficient on the dislocation density. Effects of alloying are most pronounced for the early stages of alloy addition. In copper crystals constrained by the presence of an inherent polycrystalline layer, the barrier to dislocation motion at the surface enhances secondary slip in the bulk of the material, thereby producing a significant strengthening effect. (auth)

• Research Organization: State Univ. of New York, Stony Brook (USA). Coll. of Engineering
• Sponsoring Organization: US Atomic Energy Commission (AEC)
• DOE Contract Number: AT(11-1)-3476
• NSA Number: NSA-29-016249
• OSTI ID: 4386037
• Report Number(s): COO-3476-7
• Resource Relation: Other Information: Orig. Receipt Date: 30-JUN-74
• Country of Publication: United States
• Language: English

Related Subjects

N50230* -Metals
Ceramics
& Other Materials-Metals & Alloys-Properties
Structure & Phase Studies
*COPPER ALLOYS- DISLOCATIONS
*COPPER- DISLOCATIONS
*INTERNAL FRICTION- TEMPERATURE DEPENDENCE
*NICKEL ALLOYS- DISLOCATIONS
*TUNGSTEN- INTERNAL FRICTION
BCC LATTICES
BINARY ALLOY SYSTEMS
DAMPING
DEFORMATION
DEGASSING
FCC LATTICES
FRACTURES
IMPURITIES
LOW TEMPERATURE
MEDIUM TEMPERATURE
MONOCRYSTALS
MOTION
PLASTICITY
POLYCRYSTALS
SLIP
ULTRAHIGH VACUUM
ULTRALOW TEMPERATURE
ULTRASONIC TESTING
VERY LOW TEMPERATURE