Effect of aging temperature on microstructure and mechanical properties of different rolling orientations in novel Al–Li alloy. (August 2014)

• Record Type: Journal Article
• Authors: Du, Z. L.; Zeng, W. D.; Yang, W. H.; Zhang, C.; Shi, C. L.; Wang, H. J.; Zhou, Z. P.
• Is Part Of: Materials science and technology. Volume 30:Number 8(2014:Aug.)
• Page Start: 893
• Page End: 899
• Publication Date: 2014-08
• Subjects: Materials science -- Periodicals; Microstructure -- Periodicals; Metallurgy -- Periodicals; 620.1105
• DOI: 10.1179/1743284713Y.0000000461
• Languages: English
• ISSNs: 0267-0836

Abstract

<abstract> <title> <x content-type="archive" xml:space="preserve">Abstract</x> </title> <p>Microstructure and properties of different rolling orientation with aging temperature varying in a newly developed Al–Li alloy was investigated by transmission electron microscopy (TEM) analysis. Sheets of experimental Al–Li alloy were solution treated at 510°C for 2 h. Predeformation of ∼3% was stretched in the 0 and 90° angle with respect to the original rolling orientation before aging treatment. All specimens were aged for 35 h at 138, 143, 148, 153, 158 and 163°C respectively. Tensile specimens were stretched along the previous orientation of predeformation. The results showed that the main strengthening phases in the alloy were <italic>δ</italic>′ (Al<sub>3</sub>Li), <italic>θ</italic>′ (Al<sub>2</sub>Cu)/<italic>θ</italic>″ (Guinier–Preston II zone), <italic>δ</italic>′/<italic>β</italic>′ (Al<sub>3</sub>Zr) and T<sub>1</sub> (Al<sub>2</sub>CuLi) phase. Among the phases above, the strengthening effect of T<sub>1</sub> phase surpassed the others. Moreover, very little of cubic <italic>σ</italic> (Al<sub>5</sub>Cu<sub>6</sub>Mg<sub>2</sub>) phase was observed in the alloy. The microstructure evolution was similar via comparing sheets in different stretched directions. At initial stage of aging, a large amount of fine T<sub>1</sub>, <italic>δ</italic>′, <italic>δ</italic>′/<italic>β</italic>′ and <italic>θ</italic>′/<italic>θ</italic>″ phases uniformly distributed in Al matrix with the aging temperature increasing. Subsequently, the quantity and size of T<sub>1</sub> phase increased gradually. In the middle and later period, T<sub>1</sub> phase was the main phase that grew at the cost of other phases. The peak aged temperature was 158°C with yield strength of 540 MPa when stretched at 0° angle to the original rolling orientation and 501 MPa when at 90° angle to the rolling direction. Meanwhile, the elongations were 9·5 and 10·9% respectively, which indicated that the anisotropy of the alloy was not obvious.</p> </abstract>