纯铜表面纳米化处理结构观察
1．纳米化纯铜的表面层晶粒尺寸沿厚度方向逐渐增大，呈梯度分布，由纳米量级增至微米量级，最表面晶粒尺寸最小；
2．纳米化纯铜的表面层硬度沿厚度方向逐渐减小，最表面的硬度值最大；
3．纳米化表面层的铜含量高达98%以上，受处理过程的杂质元素污染较少；
4．喷丸处理 30min 的纯铜样品表面层的平均晶粒尺寸为 20nm-30nm，晶粒取向随机分布。
毕业论文关键词 表面纳米化 旋转加速喷丸 纳米晶材料 纯铜 塑性变形
Title Micro-structures observation in copper induced by
surface nanocrystallization treatment
Abstract
Surface nanocrystallization is a promising nanotechnology that developed
rapidly in nearly two decades. In the paper, T2 pure copper was treated
by a new Rotational-Assisted-Shot-Peening (RASP) equipment in order to
achieve surface nanocrystallization. Experimental parameters include :the
impact ball diameter is 3mm, speed is 25m/s, processing time is 15min and
30min, respectively.
The surface nanocrystallization pure copper samples were tested and
characterized by scanning electron microscope(SEM) and transmission
electron microscope(TEM), the optical micro-structure and hardness tests
were also performed. Following is the results:
1.Metallographic structure on surface nanocrystallization layer of copper
treated by RASP has a gradient distribution along the thickness direction.
With increasing depth from the RASP treated surface, grain sizes increase
and vary from nano-level to micron-level;
2. The hardness on surface nanocrystallization layer of copper gradually
decreases along the thickness direction, the extreme surface layer is
maximum, respectively reached to 143HV and 125HV;
3. The copper content of the extreme surface nanocrystallization layer in
copper treated by RASP is over 98%, which shows that the copper samples
is nearly not polluted by impurity elements in the machining process;
4.The average grain size of surface nanocrystallization layer is 20nm-30nm
in copper treated by RASP, the treatment time is 30min. Meanwhile，the
crystal orientation of the surface nanocrystallization layer is random
distributed.
Keywords Surface nanocrystallization; RASP; Nanocrystalline materials; Copper; Plastic deformation。
目 次
1 绪论 . 1
1．1 表面纳米化的制备方法 1
1．2 表面自身纳米化的结构特征和性能 3
1．3 塑性变形导致纳米化机理 4
1．4 纯铜的表面纳米化研究状况 5
1．5 表面纳米化材料的应用 8
1．6 本文研究的内容 8
2 实验部分 . 9
2.1 实验材料与设备 . 9
2.2 试样的制备与测试 10