摘要本论文利用高能 X 射线实验和自洽模拟相结合的方法研究了双相钢（DP980）的微观力学行为。双相钢由铁素体和马氏体两相组成，由于二者晶体结构极其相似，高能 X射线衍射得到的材料整体的衍射峰重合在一起无法分辨，这样就给求算每一相微观应变（点阵应变）带来了困难。针对这一问题，我们利用Gauss函数对（200）晶面的整体衍射峰进行了分离，成功得到该晶面中铁素体相和马氏体相各自的衍射峰，从而求算出双相钢中各相的点阵应变和平均应力。另一方面，我们从理论计算的角度，利用弹塑性自洽（EPSC）模型模拟了双相钢的微观力学行为，发现模拟结果与实验结果拟合良好。从理论层面揭示了双相钢微观变形机制，同时也证明自洽模型在处理多相材料微观力学行为方面的有效性。 25146
毕业论文关键词 双相钢 微观应力 X射线衍射 自洽模拟
Title Elasto-plastic self-consistent simulation of micromechanical behavior in DP steel
Abstract
This dissertation focuses on the micromechanical behavior of DP steel by using
the high energy X-ray diffraction technique and self-consistent modeling. As known
to us, the dual phase steel is composed of ferrite and martensite, the crystal
structures of which are similar to each other. So the diffraction peaks obtained
by high energy X-ray diffraction of each phase are overlapped with each other,
which resulting in the difficulty in estimating the lattice strain of each phase.
In order to solve this problem, we adopt the Gauss function to separate the
integrated peak of (200) plane successfully. And the information of each peak with
different height and width is obtained. According to the information of each peak,
i. e, 2θ and full width at half maximum (FWHM), we can estimate both the lattice
strain of ferrite and martensite, respectively, and the average stress of the
integrated material. On the other hand, we used the elasto-plastic
self-consistent model to simulate the micromechanical behavior in DP steel and
the simulation results agree well with the experimental results. The simulation
results reveal the deformation mechanism in DP steel and also it indicates the
self-consistent model is a powerful tool on predicting the micromechanical
behavior of multi-phase materials.
Keywords dual-phase steel micro-stress X-ray diffraction Self-consistent simulation
目 次
1 绪论 1
1.1 双相钢研究背景. 1
1.2 双相钢国内外研究现状. 1
1.2.1 国内外双相钢发展应用概况.. 2
1.2.2 双相钢研究意义. 3
1.3 微观力学行为的表征.. 3
1.3.1 微观应力. 4
1.4 自洽模拟. 4
1.5 课题研究内容.. 5
1.6 研究目的及意义. 5
2 实验及数据处理. 6
2.1 实验材料制备及装置.. 6
2.2 硬度实验. 7
2.3 冲击拉升实验.. 8
2.4 微观结构.. 10
2.5 原位高能 X射线衍射实验.11
2.5.1 实验装置及步骤11
2.5.2 计算点阵应变 13
2.5.3 DP980 钢中点阵应变的确定 .. 13
2.5.4 结果. 14
2.6 小结. 15
3 弹塑性自洽模拟.. 16
3.1 建立双相材料中自洽模型. 16
3.2 模拟与结果讨论.. 17
3.2.1 参数. 17
3.2.2 应力应变曲线 20
3.3 结果与讨论. 20
结 论 21
致 谢 22
参考文献.. 23 双相钢微观力学行为的弹塑性自洽模拟:http://www.youerw.com/cailiao/lunwen_18784.html