Modeling of Metallic Glass Matrix Composites Under Compression: Microstructure Effect on Shear Band Evolution
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INTRODUCTION
UP to now, a variety of metallic glass composites (MGCs) have been fabricated to promote their intrinsic brittleness.[1] For instance, inorganic powders, such as SiC, SiO2, Mg, Mo, and graphite particles, have been dispersed in Mg-, Zr-, and Ti-based MGs to prepare ex situ composites[2–6]; and many in situ composites have been directly synthesized. Overall, these MGCs exhibit better compressive plasticity in contrast to their deformation ability under tension. Siegrist et al.[7] introduced graphite flakes in Vit-105 matrix and found that the compressive plasticity was inversely proportional to the inter-spacing between graphite flakes. Due to the restrictions by the current processing levels, the critical MGC samples are generally small in size, and thus, the uniaxial compression test is widely performed to measure their fundamental properties.[8] The macroscopic performances mainly rely on their inherent micro-deformation mechanisms and microstructure evolutions. Therefore, a clear understanding of these micro-deformations is helpful to guide and design the down-and-up procedures for the
YUNPENG JIANG is with State Key Laboratory of Mechanics and Control of Mechanical, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China. Contact e-mail: [email protected] KUN QIU, LONGGANG SUN, and QINGQING WU are with Department of Engineering Mechanics, Hohai University, Nanjing, 210098, China. Manuscript submitted June 7, 2017.
METALLURGICAL AND MATERIALS TRANSACTIONS A
fabrication of such composites. Balch et al.[9] used the diffraction strain measurement technique to measure the local micro-deformation in the constituents and found that the bulking of Ta particles will result in a deflect point in the stress–strain relations under compression. Kuo et al.[10] compared the microstructures and mechanical response of V-rich and Co-rich second phase filled composites and declared that the sharp V particles induced stress concentration in the amorphous matrix and lowered the mechanical performance, while the spherical Co particles would raise the mechanical properties. Wang et al.[11] explored the effect of cyclic loading on the shear banding behavior using an interrupting compression testing procedure and provided instructions for the future design of MGs with excellent fatigue performance. In real composites, many microstructure parameters are interplayed, and the individual effect of each factor is hard to be given and reflected with the real composite measurement. As an alternative method to interpret the complicated mechanisms, numerical modeling can vividly replicate some details that happen during the deformation. Based on the free volume theory, Jiang et al.[12,13] conducted parameter analyses on the roles of particle volume fraction, particle shape, particle orientation, and particle yielding strength in the enhancement of tensile ductility for MGCs. Based on the Gurson model, Biner[14] analyzed the evolution of shear banding using unit-cell-based FEM and then explained the influences of pa
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