Nanocrystallization at shear bands in bulk metallic glass matrix composites

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.

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Synthesis of Ni-based bulk metallic glass matrix composites containing ductile brass phase by warm extrusion of gas atomized powders

Journal of Materials Research ◽

10.1557/jmr.2003.0295 ◽

2003 ◽

Vol 18 (9) ◽

pp. 2101-2108 ◽

Cited By ~ 48

Author(s):

M. H. Lee ◽

D. H. Bae ◽

D. H. Kim ◽

D. J. Sordelet

Keyword(s):

Metallic Glass ◽

Bulk Metallic Glass ◽

Glass Matrix ◽

Volume Fraction ◽

Shear Bands ◽

Second Phase ◽

Matrix Composites ◽

Ductile Phase ◽

Glass Matrix Composites ◽

Warm Extrusion

To prevent catastrophic failure by propagating highly localized shear bands and to overcome the limited dimension of metallic glass, centimeter-scale Ni59Zr20Ti16Si2Sn3 bulk metallic glass matrix composites were fabricated by warm extrusion of a mixture of gas-atomized fully amorphous powders and ductile brass powders. After consolidation, the composite retained the fully amorphous matrix found in the gas-atomized powder combined with the brass second phase. The glass-transition and crystallization temperatures of the extruded material were the same as those of the starting powders. The confined ductile brass phase enabled the bulk metallic glass matrix composites to deform plastically under uniaxial compression at room temperature. The combination of strength and ductility in the inherently brittle Ni-based monolithic materials could be obtained by introducing a ductile phase in the bulk metallic glass matrix. However, control of the volume fraction and distribution of the ductile brass phase was important for the proper combination of the strength and plasticity.

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Quasi-static and dynamic deformation behaviors of in situ Zr-based bulk-metallic-glass-matrix composites

Journal of Materials Research ◽

10.1557/jmr.2010.0289 ◽

2010 ◽

Vol 25 (12) ◽

pp. 2264-2270 ◽

Cited By ~ 23

Author(s):

J.W. Qiao ◽

P. Feng ◽

Y. Zhang ◽

Q.M. Zhang ◽

P.K. Liaw ◽

...

Keyword(s):

Mechanical Properties ◽

Metallic Glass ◽

Bulk Metallic Glass ◽

Glass Matrix ◽

Dynamic Deformation ◽

Shear Bands ◽

Matrix Composites ◽

Deformation Behaviors ◽

Glass Matrix Composites

Quasi-static and dynamic deformation behaviors of Zr-based bulk-metallic-glass-matrix composites, fabricated by Bridgman solidification, were investigated in this study. Upon quasi-static compressive loading, the composites exhibit ultrahigh strength, accompanied by considerable plasticity. The multiplication of shear bands on the lateral surface of deformed samples, and the highly-dense liquid drops on the fracture surface, are in agreement with the improved plasticity. However, upon dynamic loading, the mechanical properties of the composites deteriorate considerably, due to insufficient time to form profuse shear bands. The strain-rate responses of the mechanical properties of the crystalline alloys and the in situ and ex situ bulk metallic glass composites are compared, and the different deformation mechanisms of the in situ composites upon quasi-static and dynamic loading are explained.

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