Effect of Solutionizing Time and Quenching Media on the Structure and Mechanical Properties of Al-5.6%Zn-2.5%Mg Alloy

Authors

  • C. C. Odinachi  Department of Metallurgical and Materials Engineering, Nnamdi Azikiwe University, Awka, Nigeria
  • K. C. Nnakwo  Department of Metallurgical and Materials Engineering, Nnamdi Azikiwe University, Awka, Nigeria
  • V. I. Nwoke  Department of Metallurgical and Materials Engineering, Nnamdi Azikiwe University, Awka, Nigeria
  • E. E. Nnuka  Department of Metallurgical and Materials Engineering, Nnamdi Azikiwe University, Awka, Nigeria

Keywords:

Solutionizing Time, Quenching Media, Structure, Mechanical Properties

Abstract

This research investigated the effect of solutionizing time and quenching media on the structure and mechanical properties of Al-5.6%Zn-2.5%Mg alloy. The samples were prepared using sand casting technique, machined and subjected to solution heat treatment at temperature of 300oC for 30, 90 and 150minutes respectively. Subsequently, the samples were quenched in water, brine, palm oil and SAE40 respectively. Mechanical properties such as percentage elongation, ultimate tensile strength, hardness and impact strength of the alloy were determined using JPL tensile strength tester (Model: 130812), dynamic hardness tester and impact testing machine (Model: U1820) respectively, while the alloy microstructures were studied using an optical metallurgical microscope (Model: L2003A) and scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). The microstructural analysis revealed coarse micro-segregation of intermetallic compound (MgZn2) in the control sample and presence of uniformly distributed fine grains of intermetallic compound (MgZn2) in the heat treated specimens. The results of the mechanical tests conducted showed that heat treatment significantly improved the ultimate tensile strength, impact strength and percentage elongation of the alloy. This was probably as a result of the presence of uniformly distributed fine grains of intermetallic compound (MgZn2) in the alloy structure. Heat treatment created no room for solute redistribution of Mg and Zn and hence caused the elimination of micro-segregation of MgZn2 in the alloy structure. Maximum impact strength of 12J was obtained by sample solutionized for 30 minutes and quenched in water. The control sample had the maximum hardness value which could be attributed to the presence of coarse intermetallic compound (MgZn2) in the alloy structure.

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International Journal of Scientific Research in Science, Engineering and Technology

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Published

2017-08-31

Issue

Volume 3, Issue 5, July-August-2017

Section

Research Articles

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How to Cite

[1]
C. C. Odinachi, K. C. Nnakwo, V. I. Nwoke, E. E. Nnuka, " Effect of Solutionizing Time and Quenching Media on the Structure and Mechanical Properties of Al-5.6%Zn-2.5%Mg Alloy, International Journal of Scientific Research in Science, Engineering and Technology(IJSRSET), Print ISSN : 2395-1990, Online ISSN : 2394-4099, Volume 3, Issue 5, pp.01-07, July-August-2017.