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通过数字图像相关方法获取全场应变信息,从应变非均匀性的角度研究Ni单晶体的加工硬化行为.首先提出一种适用于描述单晶体变形的数字图像相关方法,用于准确获取应变场.拉伸实验结果表明,Ni单晶体的塑性应变具有显著的局部化特征,这与滑移带的形成、发展密切相关.根据应变场的演化特征,3种变形机制可被确定,且发现它们与材料的3个加工硬化阶段具有一一对应关系.在位错理论框架下,两者之间的内在联系得到了合理的解释,并通过对材料微观结构演化的实验观测得到了很好的验证.
Through the digital image correlation method, the whole field strain information is obtained, and the work hardening behavior of Ni single crystal is studied from the perspective of strain heterogeneity.Firstly, a digital image correlation method suitable for describing the single crystal deformation is proposed to obtain the strain field accurately. The experimental results show that the plastic strain of Ni single crystal has significant local characteristics, which is closely related to the formation and development of slip band.According to the evolutionary characteristics of the strain field, three deformation mechanisms can be determined and found to be in agreement with the material 3 There is a one-to-one correspondence between the work-hardening stages.In the framework of dislocation theory, the internal relations between the two are reasonably explained and verified by experimental observations of the microstructure evolution of materials.