The morphology and quantitative analysis of the mechanisms in Alu-minium Alloy LY
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during superplastic deformation were investiga-ted by means of SEM and optical microscope. The experimental results indicate that the mechamisms of superplastic deformation of LY
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Al Al-loy in superplastic region Ⅱ are that theegrain boundary sliding (GBS) which devotes about 40-70% to total strain is the main mechanism and the diffusion creep(DC)and the dislocation slip(DIS) are accommodation mechanisms.As for superplastic region Ⅲ