Stochastic deformation and shear transformation zones of the glassy matrix in CuZr-based metallic-glass composites
Autor: | Zhiliang Ning, Yongjiang Huang, Alfonso H.W. Ngan, Kefu Gan, Sida Jiang, Jingxue Sun, Peng Xue |
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Rok vydání: | 2020 |
Předmět: |
010302 applied physics
Imagination Amorphous metal Materials science Mechanical Engineering media_common.quotation_subject 02 engineering and technology Plasticity 021001 nanoscience & nanotechnology Microstructure Condensed Matter::Disordered Systems and Neural Networks 01 natural sciences Amorphous solid Shear (geology) Mechanics of Materials 0103 physical sciences General Materials Science Shear matrix Deformation (engineering) Composite material 0210 nano-technology media_common |
Zdroj: | International Journal of Plasticity. 125:52-62 |
ISSN: | 0749-6419 |
Popis: | The incipient plasticity of an amorphous solid represents the onset of shear deformation, which is a stochastic progress closely related to microstructure evolution. It is well known that the cooling rate plays a crucial role in the microstructure evolution of a glass. Nevertheless, how the cooling rate affects the incipient plasticity is still unclear. In this work, the incipient plastic deformation of the amorphous phase in Cu47.5Zr48Al4Nb0.5 bulk metallic glass composites (BMGCs) cast with different cooling rates is systematically studied. The incipient plasticity of the glassy matrix of the BMGCs is found to occur via a first displacement burst, the occurrence of which is more stochastic as the cooling rate decreases. According to the auto-correlation functions and cooperative shear model, the stochastic behavior is attributed to the effects of the cooling rate on the initial free volume and subsequent activated shear transformation zones (STZs). A higher content of free volume is present in the glassy matrix of the studied samples cooled at a faster rate, which facilitates the operation of STZs. Moreover, the larger incipient burst size is correlated with the higher content of free volume and larger STZs in the glassy matrix. The larger STZs result in more preferable propagation of multiple shear bands, leading to less stochastic deformation and more obvious plastic deformation. This study provides further understanding on the incipient plasticity of glassy matrix in BMGCs. |
Databáze: | OpenAIRE |
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