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国际多尺度计算工程期刊
影响因子: 1.016 5年影响因子: 1.194 SJR: 0.554 SNIP: 0.68 CiteScore™: 1.18

ISSN 打印: 1543-1649
ISSN 在线: 1940-4352

国际多尺度计算工程期刊

DOI: 10.1615/IntJMultCompEng.v3.i2.70
pages 227-237

Multiscale Analysis and Numerical Modeling of the Portevin-Le Chatelier Effect

Zhongjia Chen
CAS Key Laboratory of Mechanical Behavior and Design of Materials,University of Science and Technology of China, Hefei 230027; Department of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China
Qingchuan Zhang
CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230027, China
Xiaoping Wu
CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230027, China

ABSTRACT

The Portevin-Le Chatelier (PLC) effect refers to one type of plastic instability, which often manifests itself as discontinuous yielding and localized deformation in some metallic alloys deformed under certain conditions. A phenomenological model based on a multiscale analysis is developed to investigate the PLC effect. In this model, a new component of stress is introduced, which takes account of the collective interactions between mobile dislocations and solute atoms, to describe the influence of dynamic strain aging (DSA) on the flow stress. The effects of microscopic pinning and unpinning of dislocations on the macroscopic deformation behavior are considered in an integrative and competitive manner. Due to the competition of these two effects during deformation, the alloys may exhibit the negative strain rate sensitivity of flow stress, which is a necessary condition for the occurrence of the PLC effect. A nonuniform spatial distribution of some material parameters was used in the model to reflect the heterogeneous nature of the deformed material, including a linear change of the initial cross-sectional area and a random perturbation of the initial internal stress. Numerical simulations based on this heterogeneous model were carried out for tensile testing of aluminum alloy 2017, by which the serrated yielding and localized deformation behavior were successfully reproduced. The results also indicate the relation between the macroscopic jerky flow and the pinning/unpinning of dislocations at the micro level.