Room Temperature Screw Form Rolling of AZ91D Magnesium Alloy through Processing by Extrusion-Torsion Simultaneous Working

Abstract:

Extrusion-torsion simultaneous processing is a very attractive technique for fabricating a rod-shape material with fine grain and random texture. We have proposed a new screw form rolling process combined with preliminary extrusion-torsion simultaneous working. Microstructure evolution and mechanical property change of AZ91D magnesium alloy during extrusion-torsion simultaneous processing was examined through microstructure observation, X-ray diffraction analysis and micro-Vickers hardness measurement. By the addition of torsion, the crystal orientation of AZ91D magnesium alloy workpiece was drastically changed from basal crystalline orientation to the random orientation. Crystal grain occurred through the dynamic recrystallization and tended to coarsen with an increase of extrusion-torsion temperature. Grain refinement under 2 um was achieved at the lowest extrusion-torsion temperature of 523 K. M8 gauge AZ91D magnesium alloy screw was successfully formed at room temperature using the extrusion-twisted workpiece preliminary solution treating at 678 K for 345.6 ks. It was found that the extrusion-torsion temperature of 678 K must be selected to fabricate the good screw without any defects.

• Periodical: Materials Science Forum (Volumes 783-786)
• Pages: 375-379
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.783-786.375
• Online since: May 2014
• Authors: Mitsuaki Furui*, Shouyou Sakashita, Kazuya Shimojima, Tetsuo Aida, Kiyoshi Terayama, Yusuke Ishisaka, Masayuki Yamamoto, Masayuki Ohta
• Keywords: AZ91D Magnesium Alloy, Extrusion-Torsion Simultaneous Working, Grain Refinement, Room Temperature Screw Form Rolling, Texture Randomizing

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DOI: 10.1007/978-3-319-48764-9_165

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