Grain Boundary Sliding during Low Temperature Creep of Ultrafine and Coarse Grained Aluminum

Eiichi Sato; Kaoru Ishiwata; Tetsuya Matsunaga

doi:10.4028/www.scientific.net/MSF.735.17

Paper Titles

Preface, Committees and Sponsors

Thoughts on Superplasticity in General and on its Role in Earth Deformation
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Development of High-Strain-Rate Superplastic Oxide Ceramics Based on Flow Mechanism
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Grain Boundary Sliding during Low Temperature Creep of Ultrafine and Coarse Grained Aluminum
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On the Controversy about the Presence of Grain Boundary Sliding in Mg AZ31
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Common Mechanism for Superplastic Deformation in Different Classes of Materials
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Slip Induced Strain Rate Sensitivity for Superplastic Material?
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EBSD Study of Microstructural Development during Superplastic-Like Forming
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Characteristics of the GBS – SDC Transition during Bi-Axial Forming of AA5083
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HomeMaterials Science ForumMaterials Science Forum Vol. 735Grain Boundary Sliding during Low Temperature...

Grain Boundary Sliding during Low Temperature Creep of Ultrafine and Coarse Grained Aluminum

Abstract:

HCP metals show new dislocation creep at temperatures below 0.3 Tm with stresses below σ0.2, while FCC metals show it above σ0.2. In the former, grain boundaries absorb the dislocations through slip-induced grain-boundary sliding, while in the latter dislocations are accommodated by cross slip at cell walls. The difference comes from the difference in the crystal symmetry. In UFG-Al at low temperatures, it is anticipated that grains without cell structure lead creep deformation similar to CG HCP metals rather than CG Al. UFG Al specimens were fabricated by ARB method. They showed remarkable creep behavior at less than σ0.2 similary to CG HCP metals. It posseses stress exponent of about three, grain-size exponent of almost zero, and very low apparent activation energy of 20 kJ/mol, and also grain boundary sliding behavior is obserbed by AFM.