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Effect of Li on Microstructures and Properties of Al-3.5Cu-1.5Mg Alloy |
YANG Jin-long1,2, LI Si-yu1,2, YE Ling-ying1,2, DENG Yun-lai1,2 |
1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Materials Science and Engineering (Ministry of Education), Central South University, Changsha 410012, China |
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Abstract The effect of Li on microstructures and properties of Al-3.5Cu-1.5Mg alloy was studied by optical microscopy(OM),transmission electron microscopy(TEM),scanning electron microscopy (SEM),Vickers hardness(HV)and electronic tensile test respectively. The results show that the addition of 1% Li (mass fraction) translates the main precipitation phase S'(Al2CuMg) to S' (Al2CuMg) + δ'(Al3Li) in the alloy, which Cu/Mg atom ratio is about 1. Precipitate free zones (PFZs) are narrowed. Elastic modulus increases by 8GPa. The tensile strength is improved by 21MPa. However, the elongation of the alloy decreases from 20.3% to 15.8%. The form of fracture morphology is changed from ductile fracture to ductile/brittle mixed fracture.
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Received: 12 November 2012
Published: 20 May 2013
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