The ultrasonic impact treatment (UIT) of titanium specimens leads to the grain refinement and formation of a strong basal texture in the surface layer, affecting the mechanical properties of the UIT titanium parts. In this paper, we aim at investigating numerically the effects which the UIT-modified microstructure has on the micro- and mesoscale deformation behavior of titanium specimens subjected to uniaxial tension. For this purpose, three-dimensional polycrystalline models taking an explicit account of the grain morphology and crystallographic orientations of the base material and UIT modified surface layer are generated by the method of step-by-step packing and implemented in the finite-element calculations. The constitutive models describing the nonlinear behavior of individual grains are implemented in terms of anisotropic elasticity and crystal plasticity theories. The boundary value problem is solved within a dynamic approach using the ABAQUS/Explicit package. This study allows distinguishing between the grain size and texture effects and drawing conclusions on their roles in the stress-strain evolution, plastic strain localization and deformation-induced surface roughening in UIT titanium specimens under loading.

钛试样的超声冲击处理（UIT）导致晶粒细化并在表层形成牢固的基础纹理，从而影响UIT钛零件的机械性能。在本文中，我们旨在数值研究UIT改性的微观结构对单轴拉伸钛试样的微观和中尺度变形行为的影响。为此，通过分步堆积的方法生成了三维多晶模型，该模型明确考虑了基材和UIT改性表面层的晶粒形态和结晶取向，并在有限元计算中实现。根据各向异性弹性和晶体塑性理论，实现了描述单个晶粒的非线性行为的本构模型。使用ABAQUS / Explicit软件包以动态方法解决了边值问题。这项研究可以区分晶粒大小和织构效应，并得出结论在载荷下UIT钛试样中应力应变演变，塑性应变局部化和变形引起的表面粗糙化中它们的作用。