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Vol.44, No.5, 308 ~ 317, 2006
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| Title |
| Fracture Toughness Analysis of Zr-Based Bulk Amorphous Alloys |
| 이정구 Jung G. Lee , 손기선 Kee Sun Sohn , 이성학 Sung Hak Lee , 김낙준 Nack J. Kim , 김충년 Choong Nyun P. Kim |
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| Abstract |
| The fracture property improvement of Zr-based bulk amorphous alloy containing ductile crystalline particles was explained by direct observation of microfracture processes using an in situ loading stage installed inside a scanning electron microscope (SEM) chamber. Strength of the amorphous alloy containing crystalline particles were lower than that of the monolithic amorphous alloy, while the ductility was higher. According to the in situ microfracture observation, crystalline particles initiated shear bands under low stress levels, acted as blocking sites of shear band or crack propagation, and provided the stable crack growth which could be confirmed by the R-curve analysis, although they negatively affected apparent fracture toughness. This increase in fracture resistance with increasing crack length improved overall fracture properties of the alloy containing crystalline particles. The improvement could be explained by mechanisms of blocking of crack or shear band propagation, formation of multiple shear bands, crack blunting, and shear band branching. |
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| Key Words |
| Bulk amorphous alloy, Ductile crystalline particle, Fracture toughness, Shear band, R-curve analysis |
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