Papers by Keyword: Mg Sheet

Abstract: Mg-2.0Zn-xGd sheets with non-basal texture were fabricated by common rolling process, which showed excellent ductility and formability at room temperature. In this paper, tensile tests were carried out at moderate temperature along the rolling direction and transverse direction to evaluate the influences of tensile temperature on mechanical properties and formability of the sheet. The microstructural evolution during tensile deformation was also investigated to analysis deformation mechanisms. The results showed that the elongation of the sheets increased from 57% at 373K to 253% at 573°C along the rolling direction, while the yield strength decreased with the increase of tensile temperature. The microstructure observation indicated that twining was one of the deformation modes and no dynamic recrytallization took place during deformation at 373K. With temperature increasing up to 473K, dynamic recrystallization took place and led to finer microstructure. This suggests that the formability of the Mg-Zn-Gd sheets with high ductility at room temperature could be further improved by increasing temperature up to 473K, which could refine the microstructure leading to higher strength during second forming process.

Abstract: The common joining techniques for Mg sheet and die cast alloys such as riveting, friction-stir welding and adhesive bonding all introduce additional challenges for protection in the joining areas. First of all, the sheet products are prone to high rate of corrosion due to surface contamination. Introduction of iron-rich contaminants can be encountered from the friction-stir welding process. Although powder coating on top of conversion pre-treatments is practical for mitigating corrosion, the lap-shear adhesion of such surfaces can be negatively impacted when the adhesively bonded joints are exposed to a corrosion environment. Anodized surfaces are better in terms of their ability to retain adhesion strength, but their resistance to galvanic corrosion is an issue. Development of galvanically compatible coatings for steel rivets will benefit the adaptation of riveting as a joining technology for magnesium.

Abstract: Comparing the formability with each other, extrusion and various rolling experiments were carried out to make fine-grained AZ31 Mg sheets, and uni-axial tensile tests were carried out at different strain rates and temperatures to investigate the effect of different variables. A warm deep drawing tool setup with heating elements, which were distributed under the die surface and inside the blank holder, was designed and manufactured, and deep drawing was performed. Extruded Mg alloy AZ31 sheets exhibit the best deep drawing ability when working in the temperature range 250-350°C. Extruded and rolled sheets of 0.8 mm thick were also deep drawn in the lower temperature range 105-170°C，showing good formability and reaching a Limit Drawing Ratio up to 2.6 at 170°C for rolled sheets. At last, a sheet cup 0.4 mm thick was deep drawn successfully at 170 °C.

Abstract: Canadian researchers are actively engaged in the development of novel cast, wrought and composite materials that are based on Mg. An overview is provided of Canadian research projects for new applications of Mg alloys that are targeted to the growing needs of the automotive sector. The research work described is funded primarily through two federal programs: the Canadian Lightweight Materials Research Initiative, and the Materials and Manufacturing Theme of the AUTO21 Network of Centres of Excellence. It includes work on mechanical and corrosion performance of high-pressure die castings, gravity and low pressure castings using permanent and sand molds, sheet Mg development and magnesium matrix composites. The metallurgical research facilities at the CANMET Materials Technology Laboratory are featured.