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在400℃条件下采用累积复合轧制(ARB)工艺制备Al/Zn层状复合材料。采用SEM,TEM等设备对第二轧制周期试样及第三轧制周期的试样进行显微组织观察,结果表明:在轧制过程中,Al/Zn层间界面不同成分发生相互扩散,形成扩散层;随着轧制周期的结束,扩散层中过饱和的Zn原子随温度的降低而脱溶析出,在消除晶粒边界及内部位错的同时细化晶粒。在试样内部,因为扩散层中Zn原子存在浓度梯度,过饱和的Al基体中析出的富Zn相存在不同典型的组织形态。采用万能拉伸试验机对第一、第二、第三轧制周期试样进行力学性能测试,结果显示,随着轧制周期的增加,Al/Zn层状复合材料的抗拉强度和伸长率均有大幅度提升,抗拉强度由第一轧制周期的128.81 MPa增加至第三轧制周期的351.54 MPa,提升了173%,同时伸长率由6.66%提升至11.08%。采用SEM对试样断口进行观察后发现,断口表现出明显的复合材料强界面裂纹偏转现象。采用累积复合轧制(ARB)工艺制备Al/Zn层状复合材料,因为存在复合材料强界面裂纹偏转作用以及晶粒的细化作用,表现出良好的综合力学性能。
Al / Zn layered composites were prepared by the process of accumulative composite rolling (ARB) at 400 ℃. The microstructure of the samples of the second rolling cycle and the third rolling cycle was observed by SEM, TEM and other equipment. The results show that during the rolling process, the different components of the interface between Al / Zn layers diffuse into each other, Forming a diffusion layer. With the completion of the rolling cycle, the supersaturated Zn atoms in the diffusion layer are eluted and precipitated as the temperature decreases, and the crystal grains are refined while eliminating grain boundaries and internal dislocations. Inside the sample, due to the concentration gradient of Zn atoms in the diffusion layer, the Zn-rich phase precipitated in supersaturated Al matrix has different typical morphology. The universal tensile testing machine was used to test the mechanical properties of the first, second and third rolling cycles. The results show that the tensile strength and elongation of the Al / Zn layered composites increase with the increase of the rolling cycle. The tensile strength increased from 128.81 MPa in the first rolling cycle to 351.54 MPa in the third rolling cycle, increased by 173% and the elongation increased from 6.66% to 11.08% at the same time. SEM observation of the fracture surface of the specimen showed that the fracture showed a clear deflection of the crack at the interface of the composite material. The Al / Zn layered composites prepared by the Cumulative Composite Rolling (ARB) process exhibit good mechanical properties due to the deflection of the strong interface cracks and the grain refinement of the composites.