Effects of T5 heat treatment on extrusion welds in AZ80 hollow profile |
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| Authors: | Gaoyong Lin Yuyong Wei Ke Zhou Hongyang Wang Weiyuan Song |
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| Affiliation: | 1. School of Materials Science and Engineering, Central South University, Changsha, Hunan, P.R. Chinamater218@163.com;3. School of Materials Science and Engineering, Central South University, Changsha, Hunan, P.R. China |
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| Abstract: | AZ80 hollow profile was produced by porthole-die extrusion. The mechanical behavior and microstructure characteristic of extrusion welds in AZ80 hollow profile during different T5 heat treatments were investigated. Five kinds of morphologies of β-Mg17Al12 were observed in turn in weld regions under various temperatures. Extrusion weld is not weakest region in AZ80 hollow profile in terms of hardness, the peak hardness of weld regions is roughly equal to the weld-free regions at different aging temperatures, which is attributed to similar volume fraction, morphology, and size of β-Mg17Al12 precipitate in weld regions and weld-free regions. The precipitate-free zones (PFZs) usually form near the welds interface in aging process, and the hardness of PFZs is usually lower than those of weld regions and weld-free regions. Aging at 200°C for 24?h is suitable heat treatment system for AZ80 hollow profile, which can achieve excellent mechanical property and simultaneously reduce the width of PFZs. |
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| Keywords: | AZ80 hollow profile extrusion welds mechanical behavior β-Mg17Al12 precipitate microstructural evolution porthole-die extrusion precipitate-free zones T5 heat treatment |
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