摘要梯度纳米结构材料是为了实现纳米材料在工业上的应用而被提出来的一种新材料。该材料具有良好的表面性能和综合性能，具有广阔应用前景。本课题通过旋转加速喷丸（RASP）对工业纯钛TA2进行表面纳米化并获得梯度纳米结构。在实验中控制了喷丸速度及样品厚度（及原始晶粒尺寸）制备了多组样品。通过硬度分析、金相观察、拉伸试验以及拉伸断口分析对其结构性能进行了分析，重点分析其拉伸性能，发现RASP后样品表面晶粒细化，出现大量变形孪晶，硬度明显增大，强度得到明显提升，但塑性下降较为严重。RASP后样品断口表面平整，内部有韧窝，说明RASP使样品表面硬化，塑性丧失。另外，研究结果表明，初始粗晶尺寸有显著影响。81226

毕业论文关键词  梯度纳米结构  纯钛  拉伸性能  旋转加速喷丸

毕业设计说明书外文摘要

Title    Tensile properties of gradient structured pure titanium                   

Abstract Gradient nanostructure is put forward in order to achieve the application of nanomaterials in industry。 Its excellent surface properties and global properties makes it very suitable for industrial applications。 In this paper, the industrial pure titanium was processed by Rotational Accelerated Shot Peening (RASP) treatment and gradient nanostructures were introduced into the Ti samples。 In the experiment, the speed of shot peening and the thickness of sample (and the original grain size) were controlled, and multiple sets of samples were prepared。 The hardness analysis, optical microscopy, tensile test and the tensile fracture analysis show that the samples have better hardness and strength, and the grains of surface were refined and a large number of deformation twins were found in the surface, however, the decrease of uniform elongation is also observed。 The fracture surface of samples is smooth and dimples appear in the core, indicating that the surface is harden by RASP and the ductility is lost。 Moreover, a pronounced initial grain size effect was discovered。

Keywords  Gradient nanostructure; Pure titanium; Tensile properties; Rotational Accelerated Shot Peening 

目   次

1  绪论 1

1。1  梯度纳米结构材料 1

1。2  梯度纳米结构材料的制备 2

1。2。1  表面纳米化 2

1。2。2  表面机械加工处理方法 2

1。3  梯度纳米结构材料的力学性能 2

1。3。1  拉伸性能 2

1。3。2  硬度与耐磨性 3

1。4  梯度纳米结构材料的工业应用 4

1。5  梯度纳米结构纯钛的研究现状 5

1。6  本文主要研究内容 5

2  实验部分 6

2。1  样品预处理 6

2。2  样品制备 6

2。3  性能测试及表征 7

2。3。1  硬度测试