DUCTILE-BRITTLE TRANSITION IN REFRACTORY METALS.
Abstract
The distribution of locked-in, residual strains in lightly compressed tungsten crystals with residual strains up to 0.45% has been determined by measuring the changes of interatomic spacings, delta d/d, in different crystallographic directions. It is shown that the delta d/d values measured by the divergent beam method actually represent the resolved elements of an elastic strain tensor which can be described in terms of the three principal strains. With the aid of the principal strains determined it was possible to infer the distribution of the centers of inhomogeneous strains, such as dislocations, which keep the residual elastic strains locked in the crystal. Thus the slip activity in the microstrain region is quantitatively determined. The results obtained are in good agreement with those predicted on the basis of the maximum resolved shear stress operating on potential slip planes. When the centers of inhomogeneous strains become so numerous that they affect the precision of the strain analysis, local broadening of the X-ray line profile occurs. Experimental techniques and results defining sensitively incipient line broadening are presented. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1965
- Accession Number
- AD0476108
Entities
People
- L. F. Nanni
- S. Weissmann
- T. Ellis
Organizations
- Rutgers University–New Brunswick