The α peak in cold-worked and hydrogen-loaded niobium

Abstract

Some experiments performed in an inverted torsion pendulum (90 to 300/sup 0/K, 1 and 15 Hz) on niobium in the form of marz-grade polycrystalline rods (3.18 mm in diameter). The niobium was first annealed at 2000/sup 0/K in an uhv system (10/sup -5/ Pa) for about 3 h. A bamboo structure was obtained after this treatment, and degassing was confirmed by the absence of any detectable Snoek peak (oxygen, carbon or nitrogen), and by the low macroscopic tensile yield stress at room temperature (approximately or asymptotic to 10 MPa). The internal friction spectra of this material as a function of plastic deformation was determined.