title: A size-dependent constitutive model of bulk metallic glasses in the supercooled liquid region.
abstract: Size effect is of great importance in micro forming processes. In this paper, micro cylinder compression was conducted to investigate the deformation behavior of bulk metallic glasses (BMGs) in supercooled liquid region with different deformation variables including sample size, temperature and strain rate. It was found that the elastic and plastic behaviors of BMGs have a strong dependence on the sample size. The free volume and defect concentration were introduced to explain the size effect. In order to demonstrate the influence of deformation variables on steady stress, elastic modulus and overshoot phenomenon, four size-dependent factors were proposed to construct a size-dependent constitutive model based on the Maxwell-pulse type model previously presented by the authors according to viscosity theory and free volume model. The proposed constitutive model was then adopted in finite element method simulations, and validated by comparing the micro cylinder compression and micro double cup extrusion experimental data with the numerical results. Furthermore, the model provides a new approach to understanding the size-dependent plastic deformation behavior of BMGs.
authors: State Key Laboratory of Materials Processing and Die &Mould Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, 430074 Wuhan, Hubei, China.
authors: Di
authors: D
authors: Yao
authors: State Key Laboratory of Materials Processing and Die &Mould Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, 430074 Wuhan, Hubei, China.
authors: Lei
authors: L
authors: Deng
authors: State Key Laboratory of Materials Processing and Die &Mould Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, 430074 Wuhan, Hubei, China.
authors: Mao
authors: M
authors: Zhang
authors: State Key Laboratory of Materials Processing and Die &Mould Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, 430074 Wuhan, Hubei, China.
authors: Xinyun
authors: X
authors: Wang
authors: State Key Laboratory of Materials Processing and Die &Mould Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, 430074 Wuhan, Hubei, China.
authors: Na
authors: N
authors: Tang
authors: State Key Laboratory of Materials Processing and Die &Mould Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, 430074 Wuhan, Hubei, China.
authors: Jianjun
authors: J
authors: Li
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