Ce element on ZM21 magnesium alloy and the properties

Title: Ce element on ZM21 magnesium alloy and the properties
　　Author: Fan Shibo
　　Degree-granting units: Chongqing University
　　Keywords: ZM21 magnesium alloy;; rare earth Ce;; alloying;; microstructure;; squeeze
　　Summary:
　　Deformation than the cast magnesium alloy magnesium alloy has a higher strength, better ductility, can adapt to different situations of structural parts requirements. Therefore, the development of high plasticity of magnesium alloys, magnesium alloys to suit the requirements of long-term trends. By alloying, grain refinement and other means to improve the mechanical Magnetic lifter properties of wrought magnesium alloys and processing performance, the development of new inexpensive plastic deformation of magnesium alloys have high practical significance.
　　The topics to ZM21 magnesium alloy as the matrix alloy of Ce to add elements, prepared by different Ce content ZM21 magnesium alloy to study the rare earth Ce on ZM21 magnesium alloy and performance, and optimize the optimal amount of Ce-containing ZM21 magnesium alloy. The results show that:
　　Add-cast magnesium alloy ZM21 of Ce, the tensile strength and extension of the first decreases and then increases, the Ce content of 0.39%, the tensile strength did not add more than the ZM21 magnesium alloy Ce; in the Ce content of 0.57%, the elongation restored to the level of magnesium alloy ZM21. Alloy heat deformation resistance with the addition of Ce was increasing trend.
　　Cast ZM21 magnesium alloy of Ce and Zn elements in addition to a small amount of solid solution in the base body, usually in the dendritic segregation of the gap formed at the second phase, and with the Ce content increases, the solid solution of Zn in the alloy matrix and Ce content reduced. With the increase of Ce content, the alloy of the second phase gradually increased, and finally the formation of network structure, and more and thicker due to partial polymer.
　　The cast alloy at 420 ℃ under the holding time of 10h annealing, can effectively eliminate the dendritic segregation. Alloy after annealing, precipitation of Mn from the matrix in the phase of Ce added alloy, in addition to Mg and Mn but also have high temperature stability of phase-phase and phase Mg17Ce2 CeMg12 phase. In addition, homogenization annealing temperature on the grain size of extruded products was not significant, that is, different temperature homogenization, the alloy extrusion products, grain size has little effect.
　　Extruded alloy tensile strength, yield strength have been greatly improved, especially in ZM21 alloy yield strength by a cast of more than 80Mpa to 160Mpa, # 2 # alloy 5 alloy is reached 180Mpa more # 5 of alloys close to 200Mpa. Add plastic alloy of Ce Ce are larger than 1 # do not add alloy, 4 # alloy at room temperature elongation of 24%.
　　After extrusion, with the Ce http://www.999magnet.com/products/131-magnetic-lifter content increases, ZM21 magnesium alloy gradually refined grains, when the Ce content of 0.39%, the refinement stable.
　　ZM21 magnesium alloy of Ce element in the formation of CeMg12 and Mg17Ce2 most present in the grain boundary phase or near the grain boundary strengthening in the alloy during plastic deformation broken dispersed in the alloy matrix, the stability of fine grain structure by plastic deformation and obstruction when the alloy grain boundary sliding on the plastic exert influence. When the Ce content of 0.39%, the second rare earth relative impact of two aspects of plastic equilibrium, plastic is no longer improving.
　　Degree Year: 2010