Study of deformation and ductile fracture behaviors in micro-scale deformation using a combined surface layer and grain boundary strengthening model

Interactive effect of stress state and grain size on fracture behaviours of copper in micro-scaled plastic deformation

“…In addition, it can be seen from Fig. 7(c) that the accuracy of the combined model with smooth bar is better than that of Ran's model (Ran et al, 2013), especially for the sample with a larger grain size (Li et al, 2017).…”

“…The combined constitutive model was proposed in our previous study, in which the contributions of SG, GI and GB to the flow stress of material are designated as follows (Li et al, 2017):…”

“…According to the metallographs of these specimens, the area ratios of surface grain (SG), grain interior (GI) and grain boundary (GB) are determined with ArcMap software via digital image technology. The extracted information and the true stress and strain responses of micro-scale cylinder, dog-bone and smooth bar specimens are used to determine the parameters of the combined constitutive model developed by Li et al (2017) in the corresponding deformations. The mechanical behaviour calculated by the corresponding model is then input to ABAQUS software to simulate the various deformation processes.…”

A Surface Transition Layer Model for Size Effect in T2 Copper Micro-Compression

“…The surface layer model only considers the effect of flow stress and the volume fraction of surface and inner grains on the calculation results, which are often not accurate. In recent years, based on the surface layer model, some scholars have tried to construct a more accurate model by considering plastic strain gradient hardening, such as Wang et al [21], or subdividing the inner grain into grain interior and grain boundary, such as Li et al [22]. In this paper, the nanoindentation results show that there was a transition layer between the surface layer with low flow stress and the inner layer with high flow stress.…”

Interactive effect of grain size and crystal structure on deformation behavior in progressive micro-scaled deformation of metallic materials

“…In the past few decades, a lot of efforts have been devoted to the development of new microforming process [5][6][7][8][9][10], advanced modeling methods [11][12][13][14][15][16][17], and the elucidation of the underlying physical mechanism of micro-scaled deformation. When the grain size becomes comparable with the feature size of sample in micro-scaled deformation, the individual grain property, grain morphology, and crystalline orientation could significantly affect the overall deformation response and brings up the so-called size effect, which impedes the direct application of the well-established macro-scaled knowledge to micro-scale.…”