• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.05a
• /
• pp.369-369
• /
• 2009

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2008.10a
• /
• pp.311-311
• /
• 2008

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.10a
• /
• pp.412-412
• /
• 2009

• Korean Journal of Metals and Materials
• /
• v.48 no.8
• /
• pp.699-704
• /
• 2010

We investigated the cryogenic temperature plasticity of a bulk amorphous alloy. Experiments showed that as temperature decreases, the plasticity of the alloy increases, such that the alloy exhibited ~20% of plastic strain when tested at $-196^{\circ}C$. This enhancement in the plasticity at cryogenic temperatures was associated with the formation of abundant shear bands distributed uniformly over the entire surface of the sample. Nonetheless, the serrations, the characteristic feature of the plastic deformation of amorphous alloys, were unclear at $-196^{\circ}C$. In this study, both the enhanced plasticity and the unclear serrations exhibited by the amorphous alloy at cryogenic temperatures were clarified by exploring shear banding behaviors in the context of the velocity and the viscosity of a propagating shear band.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.10a
• /
• pp.462-462
• /
• 2009

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2008.05a
• /
• pp.512-512
• /
• 2008

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.05a
• /
• pp.107-110
• /
• 2007

It has been reported that the permanent strain could happen during recrystallization and grain growth even under the externally applied stress which is much lower than yield stress. In this study, we performed dilatometry experiments under the various compressive stresses and measured the amount of recrystallization and grain growth induced permanent strain. A new constitutive equation based on the concept of boundary migration induced plasticity was suggested to describe the recrystallization and grain growth induced plasticity. This equation was verified by comparing the calculated values with dilatometric experimental data under the various compressive stresses.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.10a
• /
• pp.453-453
• /
• 2009

• Korean Journal of Metals and Materials
• /
• v.47 no.11
• /
• pp.773-785
• /
• 2009

Studies of a number of Cu-Zr amorphous alloys have demonstrated that those exhibiting greater plastic strain during homogeneous deformation at room temperature show lower global plasticity associated with inhomogeneous deformation in a typical compression test. Using a combination of experiments and molecular dynamics simulations, we clarify this seeming paradox between the homogeneous and inhomogeneous deformation by exploring the microstructural aspects in view of the structural disordering, disorder-induced softening, and shear localization and relate these findings to the global plasticity of bulk amorphous alloys. Additional analyses were conducted to derive a simple structural parameter that allows the prediction of the global plasticity of bulk amorphous alloys.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.17 no.5
• /
• pp.223-230
• /
• 2007

Plasticity of clay bodies containing bottom ashes(BA) and small portion of other wastes was investigated. Plasticity indices of clay bodies using Atterberg limits were measured. It was confirmed that the plasticity indices could be applicable in actual forming process by extrusion. The forming possible compositions were found by changing the contents of water, bottom ash, stone dust, and sewage sludge. The relationship between the plasticity and physical properties of the aggregate green body was also investigated. The compositions for extrusion forming can be expected by measured the plasticity indices and these results were confirmed by real extrusion process. There is also strong relationship between the plasticity indices and the property of aggregate green body.