| 학회 | 한국재료학회 |
| 학술대회 | 2008년 가을 (11/07 ~ 11/07, 차세대융합기술연구원) |
| 권호 | 14권 2호 |
| 발표분야 | 구조재료 |
| 제목 | Enhancement of Plasticity in Bulk Metallic Glasses with Atomic Scale Heterogeneity |
| 초록 | There are many ways to improve performances of metals and alloys by controlling alloy composition and/or their processing routes. The metallic glasses, a fully non-periodic structure, have higher strength close to Frenkel’s theoretical limit of a tenth of the shear modulus and lower Young’s modulus, which makes these materials as one of the potential candidates for structural application. Therefore, the emergence of bulk metallic glasses (BMGs) with a unique combination of properties has been an important part of the materials science arena over the past decades. However, one of the major drawbacks of BMGs is the limited global room temperature plasticity. Unlike in the case of polycrystalline metals in which the plastic strain energy can be accommodated through many pathways, the extent of the plastic deformation in BMG is dominantly dependent on the total number of shear bands (SBs) generated during deformation. Thus, methods for improving the plasticity of BMGs revolve around the question of how to generate a large number of SBs and how to impede their sudden propagation. Here, it will be focused on the optimization of compositions and processes for BMGs or BMG matrix composites with enhanced plasticity. In particular, it will be proposed that atomic scale heterogeneity originated by either embedded quasicrystal-nuclei or minor addition of element having significantly different enthalpy of mixing with constituent elements can improve plasticity of BMGs. The heterogeneity can be quantified and evaluated by fragility index, m, which closely relate to viscous flow of the BMG during deformation. Indeed, this insight is central if the correlations are to be used in the development of BMGs with high glass-forming ability and plasticity, which may contribute to BMGs receiving a great attention as a new class of structural materials. BMG is dominantly dependent on the total number of shear bands (SBs) generated during deformation. Thus, methods for improving the plasticity of BMGs revolve around the question of how to generate a large number of SBs and how to impede their sudden propagation. |
| 저자 | 박 은 수 |
| 소속 | 서울대 |
| 키워드 | Bulk Metallic Glass; Heterogeneity; Plasticity; Fragility |
