MULTI STEP HOT-WORKING OF AL-5WT.PERCENT-MG

Al-5 wt.% Mg samples were subjected to programmed torsion tests with t emperature declining from 500 degrees C to 300 degrees C to investigat e the deformation and restoration behaviour of the alloy during multi- stage hot working under non-isothermal conditions. The strong similari ty between multi-step flow curves and isothermal reference tests led t o the conclusion that the deformation of the alloy is dominated by int eractions between dislocations and Mg atmospheres and less influenced by changes in the grain and subgrain structure. The deformation above 400 degrees C is characterised by temporary breakaways of the dislocat ions from the solute atoms. Below 400 degrees C, the mobility of the M g atoms is strongly reduced and the breakaway becomes permanent.