Effects of extrusion speed and compounds on surface defects in extruded-AA7003 alloy

Abstract

The defect formation in a rod-shaped AA7003 alloy is carefully treated in the sample extruded at 10 or 20 m min⁻¹ with their structure–property relationships. The <111> + <100> double fibre texture is formed in the extruded rods, but it is altered near the surface of the extrudates due to recrystallisation and recovery, being triggered by the processing heat. This reduces strains at the region, leading to softening of the hardness. Coarse Al₉(Mn,Fe)₂Si compounds are transported to the die throat with the fragmentation. The agglomeration of compounds occurs near the surface and makes pick-up. Eventually the number of pick-up is much higher in the sample extruded at 20 m min⁻¹.

KEYWORDS:

• Aluminium alloys
• AA7003
• extrusion
• surface defect
• electron microscopy
• pick-up
• TEM
• EBSD

Acknowledgements

TH acknowledges Dr H. Yoshida of UACJ Corporation, Japan for his valuable discussion on the basic of extrusion and Professor N. Aoyagi of Nagaoka National College of Technology, Japan for the use of equipment. The members of the subcommittee, ‘The sectional meeting on simulation technique of prediction about microstructure in extruded aluminium alloy’ under The Japan Institute of Light Metals are acknowledged for valuable comments. We also acknowledge Mr Y. Asada and Ms B.K. Amalina Aina of Nagaoka University of Technology, Japan for their experimental supports.

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No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was in part supported by the subcommittee, ‘The sectional meeting on simulation technique of prediction about microstructure in extruded aluminium alloy’ of The Japan Institute of Light Metals, Japan conducted from 2015 to 2018. TH also acknowledges The Light Metal Education Foundation of Japan under Integrated Frontier Study (2017–2018).