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通过改装表面机械研磨设备,在液氮下制备出纯铜表面纳米化样品。通过显微硬度仪、拉伸试验仪、光学显微镜对样品的硬度、拉伸强度、微观组织进行测试分析。结果表明,经过液氮表面纳米化处理的纯铜样品,表面形成了硬度及晶粒尺寸逐渐变化的梯度结构;经液氮表面机械研磨(LN-SAMT)处理后,材料屈服强度提高3倍,均匀伸长率略微降低;梯度层中存在大量孪晶;样品梯度层与粗晶基体的断口呈现两种不同形貌。
By modifying the surface mechanical grinding equipment, pure copper surface nano-sized samples were prepared under liquid nitrogen. The hardness, tensile strength and microstructure of the samples were tested by microhardness tester, tensile tester and optical microscope. The results show that the gradient structure of hardness and grain size is formed on the surface of pure copper sample after liquid nitrogen surface nanocrystallization. The yield strength of material increases by 3 times after liquid nitrogen surface mechanical polishing (LN-SAMT) Uniform elongation slightly decreased; a large number of twins in the gradient layer; two different morphologies of the fracture between the sample gradient layer and the coarse grain matrix.