RELAXATION EFFECT DUE TO DISLOCATIONS IN NIOBIUM AND TANTALUM.
Abstract
The same experimental technique used in previous work on fcc and bcc metals, has been employed to investigate the influence of thermal and mechanical treatments and of the hydrogen content on the rlaxation effect already found in niobium and tantalum (FTR No. 1). The dissipation coefficient Q to the minus 1 power has been measured for several specimens of both metals having the shape of thin, circu3ar plates. In addition to the mechanical measurements, the electrical resistivity has also been measured on the same materials at several temperatures between 0 C and 100 C. From these measurements, the resistivity at 25 C has been obtained with a considerable accuracy. It has been found that the hydrogen contained in niobium and tantalum is substantially removed by a thermal treatment above 900 C, which also cancels every trace of the relaxation effect. After such a treatment the material is in a state which seems to be independent of its previous history and can therefore be taken as a reference state. The value of the dissipation coefficient in this state is of the order of 10 to the minus 5 power. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1963
- Accession Number
- AD0424622
Entities
People
- Piero G. Bordoni