Shock wave determination of the strengthening of commercial aluminum alloy 6061 by point defects

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 761; p. 138066
• Main Authors: Zaretsky, E.B., Frage, N., Kalabukhov, S.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 22.07.2019; Elsevier BV
• Subjects: Aluminum alloys; Aluminum base alloys; Atomic clusters; Control of dislocation motion; Dislocations; Elastic precursor decay; Guinier Preston zone; Point defects; Point defects in aluminum alloy 6061; Shock waves; Short range order; Solid solutions; Solution strengthening; Viscous drag; Wave propagation; Control of dislocation motion; Point defects in aluminum alloy 6061; Elastic precursor decay
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2019.138066

The strengthening of aluminum alloy 6061 (AA6061) by different point defects was determined experimentally using a shock wave technique. Decay of the amplitude of elastic precursor wave τel with propagation distance h was studied in four groups of AA6061 samples, namely, that in the super-saturated solid solution state (SSSS), and those strengthened by atomic clusters (short-range order), by Guinier-Preston zones I and by Guinier-Preston zones II after, respectively 7.5, 240 and 960 min aging of the SSSS samples at 145 °C. The dependences τel(h) were found to be kinked at stress τ*, corresponding to the transition of the control of dislocation motion from phonon viscous drag at τel>τ* to thermally activated obstacle passage at τel<τ*. The values of strengthening by atomic clusters, GP-I, and GP-II zones were found equal to τsro=67, τGP-I=67, and τGP-II=124MPa, respectively. Activation volumes corresponding to the interaction of dislocations with the studied defects, estimated based on τel<τ* segments of the measured dependences τel(h), were found to be in reasonable agreement with existing concepts of dislocation/defect interactions.