Influence of Yb Modification on the Microstructure and Mechanical Properties of A356.2 Aluminum Alloy

Abstract:

A356.2 aluminum alloy (Al–7Si–0.35Mg) has been widely used in automotive and aircraft industries. Previous studies found that the metamorphism effect of rare earth is better than other type of elements because of long modification time and good stability. The influence of Yb addition (0%, 0.2%, 0.4% and 0.6%) and T6 heat treatment on A356.2 alloy has been investigated in this work. The microstructures and mechanical properties of the specimen after T6 treatment were examined by optical microscope, scanning electronic microscope and tensile tests. Experimental results showed that Yb could reduce the size of α-Al and change the Si morphology from needle-like to fine spheroidal particles. With the increase of Yb content, the ultimate tensile strength increased gradually. When adding 0.4%Yb, the alloy achieved the highest ultimate tensile strength (252 MPa) and hardness (97.3HB), 10.12% and 37.66% higher than the alloy with no Yb addition. Tensile fracture analysis showed that the fracture mechanism for A356.2 aluminum alloy after T6 treatment is transgranular/intergranular mixed mode of fracture.

• Periodical: Materials Science Forum (Volume 898)
• Pages: 259-264
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.898.259
• Online since: June 2017
• Authors: Shao Chen Zhang, Jin Feng Leng*, Chen Xue Li, Xin Ying Teng
• Keywords: A356.2, Aging Process, Mechanical Properties, Metamorphic, Rare Earth Element

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