Nature of the Internal Friction Peak in Cold-Worked Dilute Aluminum Alloys

• Published in: Materials Transactions, JIM Vol. 40; no. 6; pp. 498 - 507
• Main Authors: Guan, Xingsheng, Numakura, Hiroshi, Koiwa, Masahiro
• Format: Journal Article
• Language: English
• Published: Sendai The Japan Institute of Metals 1999; Japan Institute of Metals
• Subjects: aluminum; anelastic relaxation; Anelasticity, internal friction, stress relaxation, and mechanical resonances; Applied sciences; cold-work; Condensed matter: structure, mechanical and thermal properties; dilute aluminum alloys; Exact sciences and technology; internal friction; Mechanical and acoustical properties of condensed matter; Metals. Metallurgy; Physics; Aluminium base alloys; Internal friction; Torsion pendulum; Snoek effect; Dilute alloys; Mechanical properties; Anelasticity; Aluminium; Cold deformation; Experimental study; Group IIIA metal
• ISSN: 0916-1821; 2432-471X
• DOI: 10.2320/matertrans1989.40.498

The origin of the internal friction peak observed for cold-worked aluminum alloys has been studied by the lowfrequency torsion pendulum technique. Internal friction has been measured for pure aluminum of various grades and dilute alloys containing Li, Mg, Si, Fe, Ga or Ge. The peak appears at 210 K (for ∼1 Hz) for unalloyed materials, as well as for the alloys, among which the peak is the largest for those with Si. The peak observed for “pure” aluminum is probably due to interaction between dislocations and impurities, such as Si. The peak exhibits asymmetrical shape when measured as a function of temperature (sharper on the low temperature side), and the activation energy and the preexponential factor of the relaxation rate τ−1 are anomalously large. These features are discussed in the light of phenomenological models of anelastic relaxation for systems where anelastic elements interact strongly with each other.