Size effect in stainless steel thin wires under tension

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:790

Article

Fu, Sichao¹  Yu, Dunji¹  Chen, Yan²  An, Ke²  Chen, Xu¹ 

[1] Tianjin Univ, Sch Chem Engn & Technol, Tianjin, Peoples R China

[2] Oak Ridge Natl Lab, Neutron Scattering Div, Oak Ridge, TN USA

关键词: Size effect;    Tension;    316L stainless Steel;    Composite modeling;    Thin wire;   

DOI  :  10.1016/j.msea.2020.139686

来源: Elsevier

【 摘 要 】

Miniaturization of modern devices drives the exploration into how materials behave in small dimensions. However, the mechanical behaviors of micro-scale specimens under varied loading conditions are still challenging to characterize and predict. In this work, specimen size-dependent weakening effect was experimentally revealed in 316L stainless steel thin wires under tension with wire diameter decreasing from 200 mu m down to 61 mu m. The underlying mechanisms were primarily associated with surface grain softening and strain localization, which were largely dependent on the number of grains across wire diameter. Through an analog composite model with surface and interior grains that follows the Hall-Petch relation, the extent of surface grain softening was found to coincide with the flow stress reduction due to lack of boundary strengthening. Further using elastoplastic self-consistent polycrystal modeling, the stress-strain behaviors of interior and surface grains were well described in analogy to those of bulk materials with similar-size grains and extremely large grains, respectively. Subsequently, the analog composite model well simulated the specimen size-dependent weakening effect under tension. This work provided more insights into the size effect exploration and proposed a practical model for describing size-dependent mechanical behaviors of small-scale materials to be applied to miniaturized devices.

【 授权许可】

Free