Effect of Ce, Gd on Rolling Properties of AZ31 Alloy

Effect of Ce, Gd on Rolling Properties of AZ31 Alloy
　　Magnesium alloys have been widely used as the light structure materials in the aviation, automotive and electronic industry due to their low density, high specific strength, specific stiffness, good damping capacity, and good shielding properties. On the other hand, wrought magnesium alloys based on microstructure refinement are the chief orientation in enhancing the strength and deformability of Mg alloy.In the present paper, rolling properties of AZ31 magnesium alloys was researched. The influence of variant content of Ce and Gd on the microstructure and rolling properties of AZ31 magnesium alloys was discussed in details. The optimal content of Ce, Gd in AZ31 was confirmed, strong magnets based which the effects of cooling velocity on rolling properties of magnesium alloys were investigated. Also, according to this, the foundation of confectioning technic and apply of magnesium alloys were supported experimentally and theoretically. The microstructure and rolling properties of AZ31 were investigated by using optical microscope(OM), scanning election microscope(SEM), Energy Dispersive Spectroscopy(EDS) and X-ray diffraction(XRD), and also the effects of the lanthanons on wrought AZ31 alloys’structure and rolling properties and it’s mechanical were studied systemically and deeply.The main contents are listed as follows:1. Different contents of Ce, Gd were added into
　　AZ31 and the effects of Ce, Gd on microstructures and grain size of AZ31 alloys were analyzed;2. Using extremal rolling experiment to test max. total rolling ratio and max. pre-pass rolling ratio of as-cast AZ31 so that we can estimate the rolling deformation abilities of casting alloys and confirm the optimal alloying component; 3. The effect of cooling velocity on rolling properties of AZ31 alloys based on the optimal addition of Ce, Gd to AZ31was investigated.The results indicate that moderate amount of Ce and Gd refine obviously the grain size of AZ31 alloy. When the content of Ce and Gd is 0.6%, 6% respectively, the refining effect is the most significant. When the content of Ce and Gd exceeds 0.6% and 6%, the grain size of alloy increases gradually with the rising content of Ce and Gd.The rod-shape Al4Ce phase appears in the microstructure of AZ31 alloy added Ce. As the http://www.chinamagnets.biz/ content of Ce increases, the amount and size of the rod-shape increase gradually and centralize in the grain boundary, and at the same time, the amount and size ofβ-Mg17Al12 phase decrease gradually. The rod-shape, quadrangular and rotundity new phase appear in grain boundary of AZ31 alloy added Gd, and as the content of Gd increases, the amount and size of new phase increase gradually and centralize in the grain boundary. Theβ-Mg17Al12 phase is not discovered in alloy added Gd.The rolling properties of AZ31 improves obviously and Max. pre-pass rolling ratio and Max. total rolling ratio increase gradually with the increasing content Ce and Gd in AZ31 alloy, but when the content of Ce and Gd exceeds 0.6% and 6% respectively, its Max. pre-pass rolling ratio and Max. total rolling ratio decreases gradually with the increasing content Ce and Gd.The max. pre-pass rolling ratio and max. total rolling ratio strong magnets increase gradually with the increasing time of homogenize heat treatment and cooling velocity. The grain size decreases gradually with heightening cooling velocity.The max. pre-pass rolling ratio and the max. total rolling rati of AZ31 added Ce, Gd which is heat treated for 2 hours is bigger than that of AZ31 without Ce, Gd and heat treated for 8 hours.