Internal Stresses in Bulk Metallic Glass Matrix Composites

AbstractComposites consisting of a bulk metallic glass (BMG) matrix and metallic fibers or particulates have been shown to exhibit superior mechanical properties as compared to monolithic BMGs. To understand the role of reinforcements in this improvement, it is necessary to investigate the state of internal stresses in these composites. These stresses arise from the thermal expansion mismatch between the reinforcement and the matrix, as well as the elastic and plastic incompatibilities between the two phases. Neutron diffraction and synchrotron X-ray diffraction were used to measure these mismatch-induced stresses in BMG-matrix composites with various reinforcements: continuous W fibers, W or Ta particles, and dendritic, in-situ formed precipitates. The results are compared to numerical and analytical predictions of internal stresses.

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Synthesis and Properties of Bulk Metallic Glass Matrix Composites

MRS Proceedings ◽

10.1557/proc-554-393 ◽

1998 ◽

Vol 554 ◽

Cited By ~ 6

Author(s):

Haein Choi-Yim ◽

Ralf Busch ◽

William L. Johnson

Keyword(s):

Metallic Glass ◽

Bulk Metallic Glass ◽

Glass Matrix ◽

Compressive Strain ◽

Matrix Composites ◽

X Ray Diffraction ◽

Glass Forming ◽

The Matrix ◽

Glass Matrix Composites ◽

Thermal Stability Of

AbstractBulk metallic glass matrix composites are processed and investigated by X-ray diffraction, DSC, optical microscopy, SEM, microprobe, TEM, and mechanical testing. Ceramics such as SiC, WC, or TiC, and the metals W or Ta are introduced as reinforcements into the metallic melt. The metallic glass matrix remains amorphous after adding up to 30 vol% of particles. The thermal stability of the matrix does not deteriorate after adding the particles. ZrC layers form at the interfaces between the bulk metallic glasses and the WC or SiC particles. Si and W are released into the matrix in which Si enhanced the glass forming ability. The composites are tested in compression and tension experiments. Compressive strain to failure increases by over 300% compared to the unreinforced Zr57Nb5Al10Cu15.4Ni12.6 and the energy to break of the tensile samples increases by over 50% adding 15 vol. % W.

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Origin of the Simultaneous Improvement of Strength and Plasticity in Ti-based Bulk Metallic Glass Matrix Composites

Journal of Materials Research ◽

10.1557/jmr.2005.0315 ◽

2005 ◽

Vol 20 (9) ◽

pp. 2474-2479 ◽

Cited By ~ 30

Author(s):

Yu Chan Kim ◽

Eric Fleury ◽

Jae-Chul Lee ◽

Do Hyang Kim

Keyword(s):

Metallic Glass ◽

Bulk Metallic Glass ◽

Coefficient Of Thermal Expansion ◽

Shear Bands ◽

Matrix Composites ◽

The Matrix ◽

The Difference ◽

Strength And Plasticity ◽

Glass Matrix Composites ◽

Classical Elasticity Theory

W-rich particle-reinforced Ti-based bulk metallic glass (BMG) matrix composites with a compressive strength approaching 3 GPa and a fracture strain of approximately 12% were developed. In contrast to most existing BMG matrix composites, in which the improved ductility was obtained only at the expense of the strength, the composites developed in this study exhibited a significant enhancement in their strength, as well as an improvement in the plasticity. This improvement in the plasticity was attributed to the blocking and circumscription of the shear band propagation, leading to the formation of a large number of shear bands. Using a classical elasticity theory of inclusions, the improvement of the strength was interpreted as resulting from the generation of tensile residual stresses in the matrix due to the difference in the coefficient of thermal expansion between the W-rich particles and the BMG matrix.

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Resolving ensembled microstructural information of bulk-metallic-glass-matrix composites using synchrotron x-ray diffraction

Applied Physics Letters ◽

10.1063/1.3506694 ◽

2010 ◽

Vol 97 (17) ◽

pp. 171910 ◽

Cited By ~ 7

Author(s):

J. W. Qiao ◽

E. W. Huang ◽

F. Jiang ◽

T. Ungár ◽

G. Csiszár ◽

...

Keyword(s):

Metallic Glass ◽

Bulk Metallic Glass ◽

Glass Matrix ◽

Matrix Composites ◽

X Ray Diffraction ◽

X Ray ◽

Glass Matrix Composites

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Microstructures and properties of the tungsten wire/particle reinforced Zr57Nb5Al10Cu15.4Ni12.6 metallic glass composites

MRS Proceedings ◽

10.1557/proc-754-cc9.9 ◽

2002 ◽

Vol 754 ◽

Author(s):

Haein Choi-Yim ◽

Jan Schroers ◽

William L. Johnson

Keyword(s):

Metallic Glass ◽

Tungsten Wire ◽

High Strength ◽

Matrix Composites ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Glass Composites ◽

Glass Forming ◽

The Matrix ◽

Glass Matrix Composites

ABSTRACTTungsten wire or particle reinforced metallic glass matrix composites are produced by infiltrating liquid Zr57Nb5Al10Cu15.4Ni12.6 (Vit106) into tungsten reinforcements at 1150 K and at 1425 K. X-ray diffraction, differential scanning calorimetry, and scanning electron microscopy are carried out to characterize the composite. The matrix of the composite processed at 1150 K is mostly amorphous, with some embedded crystals. During processing, tungsten dissolves in the glass-forming melt and upon quenching precipitates over a relatively narrow zone near the interface between the tungsten and matrix. In the composites processed at 1425 K, tungsten dissolves in the melt and diffuses through the liquid medium, and then reprecipitates upon quenching. The faster kinetics at this high temperature results uniform distribution of the crystals throughout the matrix. Mechanical properties of the differently processed composites containing wires and particles are compared and discussed. The composites exhibit a plasticity of up to 16 % without sacrificing the high strength to failure that is comparable to monolithic Vit 106.

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