Abstract
Magnesium alloys are highly desirable for a wide range of lightweight structural components. However, rolling Mg alloys can be difficult due to their poor plasticity, and the strong texture yielded from rolling often results in poor plate forming ability, which limits their further engineering applications. Here we report a new hard-plate rolling (HPR) route which achieves a large reduction during a single rolling pass. The Mg-9Al-1Zn (AZ91) plates processed by HPR consist of coarse grains of 30–60 μm, exhibiting a typical basal texture, fine grains of 1–5 μm and ultrafine (sub) grains of 200–500 nm, both of the latter two having a weakened texture. More importantly, the HPR was efficient in gaining a simultaneous high strength and uniform ductility, i.e., ~371 MPa and ~23%, respectively. The superior properties should be mainly attributed to the cooperation effect of the multimodal grain structure and weakened texture, where the former facilitates a strong work hardening while the latter promotes the basal slip. The HPR methodology is facile and effective, and can avoid plate cracking that is prone to occur during conventional rolling processes. This strategy is applicable to hard-to-deform materials like Mg alloys, and thus has a promising prospect for industrial application.
Highlights
The deformation mechanism of Mg alloys depends on a combination of grain size and crystallographic orientation
Field emission scanning electron microscopy (FESEM) observations (Fig. 3a) indicate that the resulting microstructure exhibits a typical mixed grain structure, which is mainly composed of coarse grains of 30 ~ 60 μ m (Fig. 3a,c) and fine grains that are smaller than 5 μ m (Fig. 3b)
The HPRed AZ91 plates consisted of coarse grains of 30–60 μ m, exhibiting a typical basal texture, and fine grains of 1–5 μ m as well as submicron-grains of 200–500 nm, the latter two having a weakened texture
Summary
The deformation mechanism of Mg alloys depends on a combination of grain size and crystallographic orientation For this reason, to increase the ductility of Mg alloy sheets, it needs to generate a structure containing a mixture of large grains and fine grains and requires weakening the texture of the sheets. Due to the fact that Mg alloys usually suffer from poor plasticity and are prone to oxidation, it is hard to achieve a bimodal grain structure and weakened texture simultaneously using traditional preparation method. A single-pass large-reduction rolling process results in uneven deformation, and has a probability to achieve bimodal or multimodal grain structures and weakened texture. Due to the extremely large shear forces in the rolling direction (RD), Mg alloy sheets are very prone to cracking, and this rolling technique can hardly be used for production. It is believed that our strategy is readily applicable to Mg alloys and other hard-to-deform materials, and has a promising prospect for industrial application
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
