AN X-RAY DIFFRACTION STUDY ON THE EFFECT OF RHENIUM ON THE OCCURRENCE OF FAULTING IN REFRACTORY ALLOYS.
Abstract
The bcc alloys of the terminal solid solutions of rhenium in niobium, tantalum and tungsten were investigated by several x-ray and metallographic techniques. The anisotropic particle size broadening for the cold worked Ta-10a/o Re, W-20a/o Re and Nb-Re alloys (containing less than 11a/o Re) is interpreted as evidence for stacking and/or twin faults on the (112) planes in the bcc structures. The addition of rhenium increased the fault density in the tungsten alloy, but not in the tantalum and niobium alloys. The addition of greater than 11a/o Re to niobium raises the ductile-brittle transition temperature to room temperature. These alloys fractured (when hammered) by cleavage on the (001) planes. The isomorphous Ta-10a/o Re alloy is also brittle, exhibiting (001) cleavage. Fractographic examination of the cleavage facets revealed the characteristic cleavage step and river patterns, indicating plastic deformation occurring prior to fracture. Microcracks and deformation twins associated with the crack formation were observed on sections transverse to the cleavage surface.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1964
- Accession Number
- AD0608738
Entities
People
- C. N. J. Wagner
- E. N. Aqua
Organizations
- Yale University