Grain Coarsening Behavior Of High Purity Aluminium After Critical Strain Rolling And Annealing

Grain coarsening behavior was investigated in high pure aluminum(99.99%)sample with critical strain cold rolling and subsequent annealing by means of field emission-scanning electron microscope(FE-SEM) and off-line in-situ electron back scatter diffraction(EBSD) techniques. The result showed that :1、The initial recrystallization microstructure of high pure aluminum sample with average grain size of 40-50μm developed after 90% thickness reduction cold rolling and then annealing for 3 min at 320℃.2、The critical strain of high pure aluminum sample with average grain size of 40-50μm was 10%.3、The coarse-grained microstructure of high pure aluminum sample with average grain size of 200μm developed after cold rolling with critical strain and then annealing for 15 min at 480℃.4、The misorientation between initial grains and coarse grains after annealing was defined as 10°according to counting the maximum misorientation in a grain and the sample error and so on. On this basis, we got the judgment that The coarsened grains were developed by the initial grains with critical strain and subsequent annealing instead of newly formed nucleus.5、There was no change for rolling texture with low deformation and some initial texture increased after annealing by comparative analyzing the orientation distribution function(ODF) of initial structure、critical strain structure and annealing structure. So the coarse-grained structure was developed by initial structure using the texture.6、The coarsened grains are introduced mainly by growth of the existing ones with orientations of {6 1 1}<1 0 6> and {6 1 1}<61 6>.