The influence of the rolling direction on the mechanical behavior and cavity formation during superplastic deformation of 7075 A1 alloy

• Published in: Acta metallurgica et materialia Vol. 41; no. 9; pp. 2721 - 2727
• Main Authors: Xinggang, Jiang, Jianzhong, Cui, Longxiang, Ma
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1993
• ISSN: 0956-7151; 1873-2879
• DOI: 10.1016/0956-7151(93)90141-E

The superplastic 7075A1 alloy was tested over a range of strain rates 10 −2−10 −4s −1 at a temperature range 430–510°C using specimens machined with the rolling direction parallel and perpendicular to the tensile axis. It is shown that the mechanical properties of the alloy, including the elongations to failure, are essentially identical. Microstructural observations show that the cavities tend to form in stringers and these stringers are always oriented along the tensile axis regardless of the rolling direction. The cavities are not nucleated primarily at large Fe-rich or Si-rich particles, nor do they grow from pre-existing microvoids which may be introduced during thermomechanical processing. The cavities are nucleated preferentially at small particles or some irregularities in the grain boundary during superplastic deformation.