• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.409-412
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• 2000

Much research efforts have been made on the structure and properties of metals deformed to severe plastic deformation (SPD). Being deformed to SPD, ultra-fine grains (UFG) are usually formed, and UFG structure exhibits fundamental differences in original physical properties. One method often used to obtain SPD is equal channel angular pressing (ECAP). In order for this technique to be exploited, it is important to understand the deformation behavior during the ECAP processing with respect to friction. The finite element method (FEM) has been used to investigate this issue.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.747-753
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• 2000

There has been a number of investigations in recent years reporting the results obtained on the structure and properties of metals deformed to severe plastic deformation (SPD). Being deformed to SPD, ultra-fine grains (UFG) are usually formed, and UFG structure exhibits fundamental differences in original physical properties. One method often used to obtain SPD is equal channel angular pressing (ECAP). In order for this technique to be exploited, it is important to understand the deformation behavior during the ECAP processing and relationship to the configuration of die. The finite element method (FEM) has been used to investigate this issue. It has been found that the plastic deformation is sensitive to the channel angle and material properties and is not uniform across the width of the specimen and the pressing load is relative to deformation during the ECAP processing.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.215-218
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• 2006

A study was made to investigate microstructural evolution and mechanical properties of ultra-fine grained (UFG) pure-Ti produced by equal channel angular (ECA) pressings. The deformed structures were analyzed by finite element method and transmission electron microscopy with the increment of straining. After 4 isothermal ECA pressings, initial coarse grains ($30{\mu}m$) were significantly refined to ${\sim}0.3{\mu}m$ with homogeneous distribution of microstructure which was resulted from $180^{\circ}$ rotation of the sample between pressings. UFG pure-Ti exhibited the considerable improvement in yield strength while losing strain hardening capacity as compared to coarse grained microstructure at ambient temperature, which was mainly attributed to ultra-fine grain microstructure with non-equilibrium grain boundaries.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.827-832
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• 2001

A lot of investigations have been made in recent years on the equal channel angular pressing(ECAP) which produces ultra-fine grains(UFG). Among many process parameters such as channel angles, frictions, die deformations and materials employed, the effects of material properties on the deformation behavior have been investigated. The finite element method(FEM) has been used to investigate this issue.

• Transactions of Materials Processing
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• v.27 no.4
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• pp.222-226
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• 2018

Severe plastic deformation (SPD) is a promising method for drastically enhancing the mechanical properties of the materials by grain refinement of metallic materials. However, inhomogeneous deformation during the SPD process results in the inhomogeneous microstructure of the SPD-processed material. We manufactured cylindrical copper specimens of 42 mm in diameter with ultrafine grains (UFG) using an equal channel angular pressing (ECAP) to figure out the relationship between homogeneous microstructure and the number of the processing passes. Two specimens, which are ECAP-processed 4 times (4pass) and 6 times (6pass) each with Route Bc, are prepared for comparison of mechanical properties and microstructure. The results show that the mechanical properties of the two specimens (4pass and 6pass) are similar. Moreover, both the specimens show highly enhanced mechanical properties. The 4pass specimen, however, shows inhomogeneity in hardness distribution, while the 6pass specimen shows a homogeneous distribution. Microstructure analysis reveals that the 4pass specimen has an inhomogeneous microstructure with incompletely refined grain structure. This inhomogeneity of the 4pass specimen could be explained by the circumferential rotation during ECAP process.