A novel cryogenic treatment for reduction of residual stresses in 2024 aluminum alloy

Residual stresses induced during quenching of aluminum alloys cause distortion and have a negative effect on their properties. The purpose of this study is to reduce the residual stresses and improve mechanical properties by using a novel cryogenic treatment. Water quenched samples were cooled down...

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Bibliographic Details
Published in:Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2017-03, Vol.689, p.48-52
Main Authors: Araghchi, M., Mansouri, H., Vafaei, R., Guo, Yina
Format: Article
Language:English
Subjects:
2024 aluminum alloy
Aluminum alloys
Cryogenic quenching
Cryogenic treatment
Deformation mechanisms
Drilling
Electron microscopy
Heat treatment
Heating
Liquid nitrogen
Low temperature physics
Mechanical properties
Microstructure
Precipitates
Quenching (cooling)
Residual stress
Residual stresses
Strain gauges
Tensile strength
Tensile tests
Transmission electron microscopy
Ultimate tensile strength
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Summary:Residual stresses induced during quenching of aluminum alloys cause distortion and have a negative effect on their properties. The purpose of this study is to reduce the residual stresses and improve mechanical properties by using a novel cryogenic treatment. Water quenched samples were cooled down by immersion in liquid nitrogen at −196°C, following by rapid heating in hot oil at 180°C and finally they were artificially aged. Residual stresses was measured by the hole drilling strain gauge method. The mechanical properties and microstructure of a heat treated samples were investigated by means of hardness measurements, tensile tests and transmission electron microscopy. The results showed that this treatment can relieve up to 71% of the residual stresses compared to 29% related to the traditional cryogenic treatment that used boiling water as the reheating medium. In addition, there is a considerable increase of about 75MPa in the ultimate tensile strength in comparison to the T6 heat-treated alloy. TEM observations revealed that the S′ precipitates were fine and uniformly distributed in the microstructure due to deformation during reheating in hot oil.
ISSN:0921-5093
1873-4936
DOI:10.1016/j.msea.2017.01.095