Enhanced Room-Temperature Stretch Formability of Mg–0.2 mass%Ce Alloy Sheets Processed by Combination of High-Temperature Pre-Annealing and Warm Rolling

Abstract

MgCe alloys exhibit good cold rollability. However, their room-temperature formability is known to be almost the same as that of commercial Mg alloys. In this study, Mg0.2 mass%Ce alloy sheets were processed by repeated high-temperature pre-annealing and subsequent warm rolling. The MgCe alloy sheet processed by pre-annealing at 773 K, rolling at 573 K, and then final annealing at 423 K exhibited a significantly increased Erichsen value of 8.0, which is comparable to the Erichsen values of commercial Al alloys. On the other hand, the reference material obtained by pre-annealing at 673 K, rolling at 673 K, and then final annealing at 423 K had a low Erichsen value of 3.1. The former sheet exhibited a basal texture with lower texture intensity and a larger basal pole inclination angle tilted toward the rolling direction. Extensive twinning contributed to this texture modification. In addition, fewer local deformation bands were observed in this sheet. The preannealing at 773 K, which promoted recrystallization, is thought to have resulted in the annihilation of local deformation bands. It is suggested that the enhancement of the room-temperature formability of the MgCe alloy sheets could be attributed to the synchronous effects of the texture modification and the suppression of the formation of local deformation bands.

Design and Development of Novel Wrought Magnesium Alloys

“…value of 8-9 mm, which was comparable with that of Al-Mg-Si (6XXX series) aluminum alloys (Chino et al 2008(Chino et al , 2010a. The development of such weakened texture was also reported following the addition of Ca or rare-earth (RE) elements into Mg-Zn-based alloys (Chino et al , 2010b(Chino et al , 2011Wu et al 2011;Bhattacharjee et al 2014;Bian et al 2016;Park et al 2017), and the optimization of the thermo-mechanical processing route in Mg-Zn and Mg-Al alloys Huang et al 2009Huang et al , 2011Huang et al , 2012Huang et al , 2015aSuzuki et al 2015;Yi et al 2016;Trang et al 2018).…”