Microstructure and high temperature deformation of an ultra-fine grained ECAP AA7075 aluminium alloy

2013 ◽  
Vol 104 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Přemysl Málek ◽  
Kryštof Turba ◽  
Miroslav Cieslar ◽  
Petr Harcuba
Keyword(s):  
High Temperature ◽  
Aluminium Alloy ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Fine Grained

Superplastic Elongation through Deformation Mechanism Transition during High-Temperature Deformation in Thermally Unstable Fine-Grained Aluminum Solid Solution Alloy

2016 ◽  
Vol 723 ◽  
pp. 21-26
Author(s):  
Tsutomu Ito ◽  
Takashi Mizuguchi
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Deformation Mechanism ◽  
Solute Drag ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Solid Solution Alloy ◽  
Fine Grained ◽  
Aluminum Solid Solution ◽  
Mechanism Transition

In this study, the superplastic behavior on a fine-grained aluminum solid solution alloy consisting of thermally unstable microstructures was investigated. In order to obtain the fine-grained microstructure, friction stir processing (FSP) was applied to a commercial 5083 aluminum alloy. An equiaxial fine-grained microstructure of 7.8 mm was obtained after FSP, but this microstructure was thermally unstable at high temperatures. Commonly, for fine-grained superplasticity to occur (or to continue grain boundary sliding (GBS)), it is necessary to keep the fine-grained microstructure to less than 10 mm during the high-temperature deformation. However, in this study, a large elongation of over 200% was observed at high temperatures in spite of the occurrence of grain growth. From the microstructural observations, it was determined that the fine-grained microstructure was maintained until the early stage of deformation, but the transgranular deformation was observed at a strain of over 100%. The microstructural feature of the abovementioned transgranular deformation is similar to the deformation microstructure of the solute drag creep occurring in "Class I"-type solid solution alloys. This indicates that the deformation mechanism transition from GBS to the solute drag creep occurred during high-temperature deformation. Here, the possibility of occurrence of the superplastic elongation through deformation mechanism transition is discussed as a model of the thermally unstable aluminum solid solution alloy.

The effect of stress state on high-temperature deformation of fine-grained aluminum–magnesium alloy AA5083 sheet

2009 ◽  
Vol 57 (9) ◽  
pp. 2812-2822 ◽  
Author(s):  
Eric M. Taleff ◽  
Louis G. Hector ◽  
John R. Bradley ◽  
Ravi Verma ◽  
Paul E. Krajewski
Keyword(s):  
High Temperature ◽  
Stress State ◽  
Magnesium Alloy ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Fine Grained ◽  
Aluminum Magnesium Alloy
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