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The influence of heat treatment on the structure and tensile properties of thin-section A356 aluminum alloy casts refined by Ti, B and Zr

Published online by Cambridge University Press:  29 May 2017

Masoud Emamy ,
Mehdi Malekan ,
Amir Hosein Pourmonshi  and
Kourosh Tavighi
Masoud Emamy
Affiliation:
School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran 1417614418, Iran
Mehdi Malekan*
Affiliation:
School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran 1417614418, Iran
Amir Hosein Pourmonshi
Affiliation:
Department of Materials Engineering, Islamic Azad University, South Tehran Branch, Tehran 1777613651, Iran
Kourosh Tavighi
Affiliation:
School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran 1417614418, Iran
*
a) Address all correspondence to this author. e-mail: mmalekan@ut.ac.ir
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Abstract

The aim of this study is to investigate the effects of different master alloys containing Ti, B, and Zr on the structure and tensile properties of thin-section A356 aluminum alloy in as-cast and T6-treated conditions. Microstructural examinations were performed using light optical and scanning electron microscopy. The results showed that the addition of 0.1 wt% Ti, 0.05 wt% B, and 0.1 wt% Zr decreases the average grain size of the cast alloy from 840 μm to 387 μm, 236 μm, and 363 μm, respectively. This structural refinement results in the variation of the α-Al primary phase distribution mode from dendritic to rosettelike. It has been found that 0.6 wt% Al–8B master alloy (0.05 wt% B) is the strongest to refine the structural parameters. This leads to the enhancement of both ultimate tensile strength and elongation values from 208 MPa and 6.2% in as-cast to 290 MPa and 12.5% in B-refined alloy at T6-treated conditions. In addition, the presence of more fine dimples on the fracture surfaces of the T6-treated specimens revealed that T6-treatment encourages ductile mode of fracture.

Keywords

aluminum alloygrain refinementstructureheat treatmenttensile propertiesfracture
Type
Articles
Information
Journal of Materials Research , Volume 32 , Issue 18 , 28 September 2017 , pp. 3540 - 3547
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Copyright
Copyright © Materials Research Society 2017 

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Footnotes

Contributing Editor: Jürgen Eckert

References

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