| 张雪薇,李超,罗胜年*.晶粒取向和晶界对双晶铜变形的影响[J].实验力学,2019,34(3):406~412 |
| 晶粒取向和晶界对双晶铜变形的影响 |
| On the effect of grain orientation and grain boundary on the deformation of bicrystal copper |
| 投稿时间：2017-11-01 修订日期：2019-03-31 |
| DOI：10.7520/1001-4888-17-228 |
| 中文关键词: 双晶铜 数字图像相关方法 滑移带 |
| 英文关键词:bicrystal copper digital image correlation method slip band |
| 基金项目:国家自然科学基金(11627901, 11372113, 11672110)资助 |
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| 中文摘要: |
| 在扫描电子显微镜(SEM)下拉伸双晶铜样品，用数字图像相关方法(DIC)处理样品在不同应变状态下的SEM图片，得到正应变场Exx和剪应变场Exy，并通过Exx和Exy的演化研究双晶铜的变形特征，以及晶粒取向和晶界对它的影响。正应变场Exx显示两晶粒内部、晶界附近分别有单、双系滑移开启，滑移带会造成局部变形的不均匀。随着应变的增加，滑移带数量增多而强度减小，变形趋于均匀化。相比软取向晶粒，硬取向晶粒中的滑移带数量少而滑移带强度高。剪应变场Exy幅值远小于Exx幅值，因而观察不到滑移带。软取向晶粒比硬取向晶粒的平均正应变Exx大，它们之间的差别在8%的拉伸应变后随着应变的增加而被放大，晶界产生更高的协调应力，使得晶界附近的剪应变Exy开始急剧增加。 |
| 英文摘要: |
| Bicrystal copper sample is stretched under scanning electron microscope (SEM). SEM sample pictures obtained under different strain states are processed by digital image correlation (DIC) method. The normal strain field Exx and shear strain field Exy are obtained. The deformation characteristics and influence of grain orientation and grain boundary (GB) on deformation of bicrystal copper are studied based on Exx and Exy evolution. Normal strain field Exx reveals that the single and double slip systems are activated at two grain interiors and GB vicinity, respectively. Slip band may result in unhomogeneity of local deformation. With the increase of strain, the number of slip band increases, but the strength decreases and the deformation tends to homogenous. Compared with soft-oriented grains, there are fewer slip bands and higher strength of slip bands in hard-oriented grains. The amplitude of shear strain Exy is much smaller than that of normal Exx, so the slip bands can't be observed in shear strain field Exy. The average normal strain (Exx) of soft orientation grain is larger than that of hard orientation grain. The difference between them is amplified with the increase of strain after reaching 8% tensile strain. Higher coordinated stress at grain boundaries leads to a sharp increase in shear strain Exy near grain boundaries. |
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