STRAIN-RATE DEPENDENCE OF MECHANICAL-PROPERTIES IN AA5056 AL-MG ALLOYPROCESSED BY EQUAL-CHANNEL-ANGULAR-EXTRUSION

Microstructure of AA5056 Al-Mg alloy is refined dramatically by the eq ual-channel-angular-extrusion (ECAE) process. Tensile properties at ro om temperature in the ECAE-processed 5056 Al-Mg alloy (5056-ECAE) are characterized as a function of strain rate. Total elongation of 5056-E CAE increases with strain rate in the same way as some fully annealed Al-Mg alloys, and the result supports the possibility of using the all oy for high-rate forming. Yield stress (YS) and ultimate tensile stren gth (UTS) in 5056-ECAE exhibit remarkably higher values than those of the fully annealed 5056 alloy (5056-O). UTS of 5056-ECAE is almost ind ependent of strain rate below the strain rate of 6.5 x 10(2) s(-1); co mpared.with 5056-O. Change in the strain rate sensitivity of UTS may b e caused by the difference in the interaction between solute atoms and dislocations. (C) 1998 Elsevier Science S.A. All rights reserved.