循环载荷下表面强化工业纯锆残余应力释放研究

发布时间：2018-04-24 06:08

本文选题：工业纯锆 + 循环加载　；参考：《稀有金属材料与工程》2015年10期

【摘要】：对工业纯锆进行表面机械研磨处理(SMAT),实现其表面纳米化,并引入残余压应力场。采用偏光显微镜(PM)、透射电子显微镜(TEM)对SMAT处理试样显微组织进行表征,利用X射线应力仪测试不同循环加载周次下距试样表面不同深度处宏观残余应力。研究不同循环加载周次下距表层不同深度处X射线衍射峰半高宽的变化特征,并采用Voigt函数拟合X射线衍射峰,得到微观应变和位错密度的分布特征。结果表明:循环加载初期残余应力释放率最大,约为25%,随着循环加载周次增加残余应力释放率趋于稳定;不同循环加载周次下,随距表层深度增加,X射线衍射峰半高宽、微观应变和位错密度逐渐降低后趋于稳定;随着位错密度降低,残余压应力逐渐增加,位错密度值稳定于约2×1010cm-2时所对应的深度,和最大残余压应力对应的深度基本一致。循环载荷下残余应力释放是通过微观塑性变形过程中位错运动来实现。
[Abstract]:Surface mechanical grinding of industrial pure zirconium was carried out to realize surface nanocrystallization and residual compressive stress field was introduced. The microstructures of SMAT treated samples were characterized by polarizing microscope and transmission electron microscope (TEM). The macroscopic residual stress at different depth from the surface of SMAT was measured by X-ray stress analyzer. The variation characteristics of the width of the X-ray diffraction peak at different depths from the surface layer under different cyclic loading cycles are studied. The distribution characteristics of the microscopic strain and dislocation density are obtained by fitting the X-ray diffraction peak with the Voigt function. The results show that the release rate of residual stress is the largest at the beginning of cyclic loading, about 25%, and tends to be stable with the increase of cycle loading cycle, and the width of X-ray diffraction peak increases with the depth of surface layer under different cycle loading cycles. With the decrease of dislocation density, the residual compressive stress increases gradually, and the dislocation density is stable to the corresponding depth of about 2 脳 1010cm-2, and the depth corresponding to the maximum residual compressive stress is basically the same as that of the maximum residual compressive stress. The release of residual stress under cyclic loading is realized by dislocation movement during micro plastic deformation.
【作者单位】：西安建筑科技大学;
【基金】：国家自然科学基金青年基金(51104114);国家自然科学基金(51274160) 碑林区科技局科技计划项目陕西省教育厅科技项目(13JS061)
【分类号】：TG580.6;TG146.414

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