SOME ASPECTS OF DEFORMATION IN SINGLE CRYSTALS AND BICRYSTALS OF ALUMINUM AT ELEVATED TEMPERATURES
Abstract
A study was made to evaluate the kinematics of grain boundary shear and to compare the results pertaining to crystallographic deformation with those reported in the literature. Melt-grown single crystals and bicrystals of high purityAl were tested in tension at extension rates of 8.20 x 10 to the -6th power to 10 to the -4th power cm/sec (strain rates of approximately 2.3 to 230%/hr) and at temperatures of 538 to 650 C. The bicrystal samples contained pure, symmetrical tilt or twist boundaries of 10, 32, 40, 88, and 90 degrees. Continuous stress and total extension and intermittent shear displacement data were obtained as a function of time. A yield point phenomenon which is caused by a small amount of pre-test deformation was observed for single crystals and to a reduced extent for bicrystals. Its presence is explained by a model based upon dislocation multiplication and the stress dependent velocity of dislocations. A yield stress for grain boundary shear which is associated with a thermally activated process was also observed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1961
- Accession Number
- AD0262462
Entities
People
- Arthur N. Lord
- Richard H. Bush
Organizations
- Stanford University