STRAIN-RATE SENSITIVITY OF HOT DEFORMED AL AND ALMGSI ALLOY

Hot compression tests, at a constant true strain rate, were performed on a solution treated AlMgSi alloy. Strain and precipitation hardening of the alloy was observed during deformation at intermediate temperat ures. The hardness maximum for was observed at deformation temperature s of specimens deformed to epsilon = 0.5 at strain rate of 1.3 x 10(-2 ) s(-1) and 1.3 x 10(-3) s(-1) 510 K and 470 K respectively. Strain ra te sensitivity measurements were performed during hot deformation in t he strain range of epsilon = 0.05-0.5. For comparison, additional test s were also performed for the overaged alloy, and for pure aluminium, to test the effect of solutes and structural changes during deformatio n. The strain rate sensitivity was found to be temperature dependent f or the materials used in the experiment. Moreover, the strain rate sen sitivity of solution treated AlMgSi alloy was found to be strain depen dent and possible reasons of this effect were discussed.