A Maxwell-extreme constitutive model of Zr-based bulk metallic glass in supercooled liquid region

• The flow behavior of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass in supercooled liquid region were investigated.
• Effects of temperature and strain rate on viscous flow and stress overshoot were studied.
• A new model was proposed by considering the temperature and strain rate dependences of viscous flow and stress overshoot.
• The validity of Maxwell-extreme constitutive model was confirmed by FE simulation method.

The uniaxial compression tests were performed to research the deformation behavior of Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit1) bulk metallic glass (BMG) in a wide range of strain-rates and temperatures. The true stress-strain curves in the supercooled liquid region (SLR) fitted by Maxwell-pulse constitutive model have been compared with the experimental data. It was found that there were larger deviation between the true stress-strain curves obtained from compression tests and Maxwell-pulse model. In order to describe the whole flow process more accurately, the influences of ambient temperature and strain rate on viscous flow and stress overshoot related to structural relaxation, which were ignored in Maxwell-pulse model, were introduced to construct a new constitutive relationship of Vit1 alloy in SLR. The constitutive models before and after modified were then written into the finite element (FE) simulation software, respectively. It was provided that the fitting results simulated by the new constitutive model were in better agreement with the uniaxial compression test data than those of Maxwell-pulse.

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