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Microstructure and Mechanical Properties of Cast Al-5Zn-2Mg Alloy Subjected to Equal-Channel Angular Pressing

  • G. K. Manjunath
  • G. V. Preetham Kumar
  • K. Udaya Bhat
  • Prashant Huilgol
Article
  • 27 Downloads

Abstract

In the present work, cast Al-5Zn-2Mg alloy was processed through equal-channel angular pressing (ECAP) in route BC up to four number of passes. Microstructure and mechanical properties were investigated on processed and unprocessed materials. In cast condition, the material was composed of dendritic structure. After homogenization treatment, large-sized grains were observed. After ECAP processing, significant grain refinement was observed. After ECAP processing, high-density dislocations and high degree of misorientation between the grains were observed. In cast material, rod-shaped precipitates were observed, while, after ECAP processing, spherical-shaped precipitates were observed. ECAP processing leads to a noticeable improvement in the mechanical properties of the material. After four passes, 122% improvement in the microhardness and 135% improvement in the ultimate tensile strength of the material were observed. After three passes, a slight decrease in the mechanical properties was observed. This is attributed to the dissolution of the metastable η′ phase, annihilation of dislocations, dynamic recrystallization and texturing during ECAP processing. Brittle fracture mode was observed in tensile testing cast and homogenized samples. After ECAP processing, fracture mode was changed into shear fracture mode.

Keywords

Al-Zn-Mg alloy ECAP grain refinement mechanical properties x-ray diffraction analysis 

Notes

Acknowledgments

One of the authors Mr. G.K. Manjunath would like to thank the Director, National Institute of Technology Karnataka and MHRD-Government of India for providing Institute Research Fellowship.

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Copyright information

© ASM International 2018

Authors and Affiliations

  1. 1.Department of Metallurgical and Materials EngineeringNational Institute of Technology KarnatakaSurathkal, MangaloreIndia

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