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利用OM,SEM,TEM,数字显微硬度计和电子万能试验机,对常规轧制与铸轧法制备的AZ451镁合金薄带的显微组织和力学性能进行了分析.常规铸锭轧制后仍为等轴晶组织,晶粒尺寸明显细化.铸轧条带在350℃多道次轧制后显微组织由树枝晶转变为纤维状变形组织,350℃/10 min热处理后合金发生再结晶,得到等轴晶组织.轧制后两种合金均具有良好的力学性能,双辊铸轧合金的强度和延伸率均明显高于传统铸造合金的强度和延伸率,两种合金1 mm厚薄带经350℃/10 min均匀化退火后的抗拉强度、屈服强度和延伸率分别为334.4 MPa,229.3 MPa,23.8%和270.8 MPa,174.4 MPa,10.8%.两种合金的断口形貌均呈现河流花样,撕裂棱和韧窝共存,是明显的韧性断裂,铸轧合金的韧窝更明显,尺寸更小一些,这与铸轧合金的组织更细小有关.
The microstructure and mechanical properties of AZ451 magnesium alloy strip prepared by conventional rolling and casting methods were analyzed by using OM, SEM, TEM, digital microhardness tester and electronic universal testing machine. The microstructure is still equiaxed and the grain size is obviously refined.The microstructure of the casting strip transformed from multi-pass rolling at 350 ℃ to dendritic microstructure, and then the alloy is annealed at 350 ℃ for 10 min Crystallization and equiaxed grain structure.The two alloys have good mechanical properties after rolling.The strength and elongation of the twin-roll cast alloy are significantly higher than the strength and elongation of the traditional cast alloy, the thickness of the two alloys 1 mm The tensile strength, yield strength and elongation of the ribbon annealed at 350 ℃ / 10 min were 334.4 MPa, 229.3 MPa, 23.8% and 270.8 MPa, 174.4 MPa and 10.8%, respectively. River patterns, tearing edges and dimples coexist, is a clear ductile fracture, casting alloy dimples more obvious, smaller size, which is the structure of the alloy rolling more small.