Internal friction in hydrogen-charged aluminium alloys

Abstract

Abstract Measurements of the internal friction of aluminium alloys containing hydrogen have been made from 77 to 300 K at 35 kHz using a composite resonator technique. Perfection of a metallic bonding technique for the transducer-specimen composite produced background dampings which were typically of the order Q −1 ≃ 10−6. Criteria which relied on measurements at harmonic frequencies were used to distinguish internal friction in the specimen from spurious damping caused by the suspension or the joint. The results were used to place limits on the possible values of binding energies of 0·05 eV between hydrogen and copper solutes and of 0·06 eV between hydrogen and magnesium solutes using a simple model of the interstitial-hydrogen distribution in the alloy.