Characterization of As-Grown Dislocation Structure in Niobium by X-Ray Diffraction Topography.
Abstract
The behavior of dislocations in b.c.c. metals has been extensively examined using relatively macroscopic methods, such as deformation studies and etch pitting, as well as with microscopic TEM methods. While these studies have led to significant increases in the understanding of dislocation behavior, the need remains for a method for studying the microscopic behavior of dislocations in relatively thick specimens. One such method, x-ray diffraction topography, has not been extensively applied due to the relatively high x-ray absorption of many of the metals of interest, such as niobium, and the consequent need to prepare highly perfect thin crystals. In the present note we report the preparation of such niobium crystals and the use of Lang topography to characterize their dislocation structures. Single crystal niobium specimens of thickness suitable for transmission topographic studies were grown by recrystallization of a heavily deformed polycrystalline ribbon of niobium. The procedure consisted of resistance heating at 2200K and 2.6 times 10 to the minus 8th power Pa for times on the order of an hour. It should be noted, however, that due to outgassing of the niobium, protracted annealing was required to obtain this pressure.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1981
- Accession Number
- ADA105431
Entities
People
- Hayden Chen
- Howard K. Birnbaum
- Stuart R. Stock
Organizations
- University of Illinois Urbana–Champaign