A finite-deformation constitutive model for bulk metallic glass composites

Advanced Composites Letters

2018

In this contribution, an analytical model was formulated to predict the tensile stress-strain relations of bulk metallic glass matrix composites (BMGCs) based on Weng's theoretical frame for dual-ductile composites. For in-situ BMGCs, BMG matrix also exhibits the elastic-plastic deform response as well as the dendrite phases during the stretching. The shear bands are regarded as Mode-I cracks, and whereby the strain-softening stage in the stress-strain curves can be well reflected. Furthermore, multi-particle representative volume element based FEM modelling was employed to clearly explain the failure mechanisms in BMGCs as a necessary complement. The predictions are in reasonable agreement with the experimental results. The presented analytical method will shed some light on optimizing the microstructures, and is of convenience in the engineering applications.

Section: Shear Banding Effectmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Analytical Method for Studying the Stress-Strain Relations of Bulk Metallic Glass Matrix Composites under Tension

Advanced Composites Letters

2018

“…It is imperative to understand the correlations among processing, microstructures and properties for such composites. According to the thermodynamics and free energy principle, Marandi et al [ 1 ] advanced an elastic-viscoplastic constitutive model for describing the finite deformation behaviors of BMGCs. They [ 2 ] further extended their model to better predict the stress–strain relations of in-situ BMGCs.…”

Section: Introductionmentioning

confidence: 99%

Mesoscopic Constitutive Model for Predicting Failure of Bulk Metallic Glass Composites Based on the Free-Volume Model

2018

Materials

A meso-mechanical damage model is developed to predict the tensile damage behaviors of bulk metallic glass composites (BMGCs) toughened by ductile particles. In this model, the deformation behaviors of the BMG matrix and particles are described by the free volume model and Ludwik flow equation, respectively. Weng’s dual-phase method is used to establish the relationship between the constituents and the composite system. The strain-based Weibull probability distribution function and percolation theory are adopted in characterizing the evolution of shear bands leading to the progressive failure of BMGCs. Moreover, the present model is performed under strain-controlled loading. Comparing to experiments on various BMGCs, the predictions are in good agreement with the measured results, which confirms that the present model successfully depicts the composite properties, such as yield strength, uniform deformation and strain softening elongation.

“…Moreover, the analytical models are more efficient in guiding the design, synthesis, and evaluation of BMG composites (Kim and Lee, 2011;Li and Sun, 2013) but now lag far behind the experiments and numerical simulations. Based on the principle of thermodynamics and free energy, Marandi and Shim (2014) developed an elastic-viscoplastic, three-dimensional, finite deformation constitutive model to describe the large deformation behavior of BMG composite, but their model is fairly complicated and is short of the micromechanics significance. Qiao et al (2013) firstly presented a mathematical model to elucidate the work-hardening behavior of ductile dendrites and softening of the amorphous matrix, and fatherly predicted the tensile response of BMG composites, but the interaction between the two phases was not well considered yet.…”

Section: Introductionmentioning

confidence: 99%

A micromechanics-based incremental damage theory of bulk metallic glass matrix composites

International Journal of Damage Mechanics

Tohgo

Shimamura

2015

Based on the Mori-Tanaka's mean field concept, a micromechanics-based incremental damage theory was developed to investigate the mechanical performance of bulk metallic glass matrix composites under tension. Firstly, the shear band was considered to be a microcrack, and therefore a spherical fictitious inclusion-containing microcracks and the surrounding bulk metallic glass matrix were constructed. Based on the equivalence between the effective elasticity of microcrack-containing media and porous material, the volume fraction of the fictitious inclusion could be determined by the density of microcracks generated during a strain increment. The stress-based Weibull probability distribution function and percolation theory were applied to describe the microcrack evolution that results in the progressive damaging of bulk metallic glass composites. Based on the present model, the impact of shear bands on the tensile ductility was discussed for the composites with various microstructures. The predictions are in fairly good agreement with the experimental data, demonstrating that the developed analytical model is capable of successfully capturing the main features, such as yield strength, strain hardening, and stress softening elongation, of particle-toughened bulk metallic glass. The main conclusions will shed some light on optimizing the microstructures in effectively improving the tensile ductility of bulk metallic glass composites.