期刊
INTERNATIONAL JOURNAL OF PLASTICITY
卷 152, 期 -, 页码 -出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.ijplas.2022.103232
关键词
Metallic glasses; Bicontinuous structure; Nanoporous structure; Deformation behavior
资金
- National Natural Science Foundation of China [51821001]
- MOST 973 Program [2015CB856800]
The mechanical properties and plastic deformation of a Cu(55.4)Zr(35.2)Al(7.5)Y(1.9) nanoporous metallic glass (MG) were studied. It was found that the nanoporous MG is brittle in tension and has significant homogeneous plasticity under compression. The study clarifies the fundamental failure mechanism and deformation behavior in nanoporous MGs.
The mechanical properties and plastic deformation of a Cu(55.4)Zr(35.2)Al(7.5)Y(1.9 )nanoporous metallic glass (MG) have been studied using depth-sensing nanoindentation combined with electron microscopy characterization. The nanoporous MG exhibits an initial relative density of 50.9% and a bicontinuous structure with 20.84 +/- 1.49 nm-diameter interconnecting ligaments. It is brittle in tension, whereas it has significant homogeneous plasticity under compression. It has a hardness of 0.67 +/- 0.06 GPa and Young's modulus of 14.72 +/- 0.74 GPa from nanoindentation. While under tensile and compression, it has a yield strength of 0.22 to 0.23 GPa and an effective modulus of 10.37 +/- 0.99 GPa. The discrepancy between the moduli is caused by irreversible shear transformation zone (STZ) plasticity that takes place well ahead of the yield point. The deformation in the nanoporous MG begins with both elastic and plastic bending in ligaments and transfers to plastic uniaxial deformation in ligaments at a critical strain near 0.03, at which a significant change in stiffness is observed. The yielding stress follows the universal scaling law predicted by the critical-like behavior in glassy systems. The strength to modulus ratio is well maintained in this nanoporous MG and is higher than the porous crystalline alloys. Our experimental study clarifies the fundamental failure mechanism and deformation behavior in nanoporous MGs.
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