Article ID Journal Published Year Pages File Type
7981379 Materials Science and Engineering: A 2014 7 Pages PDF
Abstract
Experiments were conducted on a commercial Al-7075 alloy by processing by ECAP for 4 passes and then processing by HPT for up to a maximum of 20 turns. Measurements show that the grains were refined to ~680 nm after ECAP and to ~310 nm in the center of the disk after ECAP+HPT. Tensile testing at a temperature of 623 K revealed lower flow stresses and higher elongations to failure after processing by ECAP+HPT. Thus, the alloy was not superplastic after processing by ECAP but superplasticity was achieved with elongations up to ~800% after processing by ECAP+HPT. By plotting the Vickers microhardness against equivalent strain, it is shown that the hardness saturates at Hv≈250 after ECAP+HPT. This saturation hardness is higher than the value of Hv≈230 recorded after processing by HPT without a preceding step of ECAP. The results demonstrate that processing by ECAP+HPT produces higher hardness and greater grain refinement than processing only by HPT.
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Physical Sciences and Engineering Materials Science Materials Science (General)
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