| 다공성 소결 순철에서 인장연성의 변화에 관한 연구 |
| 정재영, 손호상 |
1경북대학교 자동차부품소재연구소
2경북대학교 공과대학 신소재공학부 |
| A Study on the Variation in Tensile Ductility of Porous Sintered Iron |
| Jae-Young Jung, Ho-Sang Sohn |
1Automobile Parts & Materials Research Center, Kyungpook National University, Daegu 41566, Republic of Korea
2School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, Republic of Korea |
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Received: 24 July 2017; Accepted: 18 October 2017. Published online: 1 January 2018. |
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| ABSTRACT |
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A model based on Irwin's approach to elastic-plastic deformation was applied to predict the tensile ductility of a sintered iron. The evaluation of this model using experimental results for porous sintered iron showed that tensile ductility depends not only on the pore volume fraction, but also the pore size and the mechanical properties of the matrix. It was shown that this model agrees well with experimental data and resolves some of the discrepancies of the Brown-Embury model. This model suggested that the ductility of the porous metal can be improved by actively controlling the metallurgical parameters, such as the mechanical properties of the matrix and the pore size. It can be seen that the fracture true strain of the base metal has the same effect as the change in pore radius, because it acts as a linear function in the ductility prediction of porous iron. On the other hand, the σ my/△Kth,eff ratio varies from the quadratic function. The calculation results based on this model show that effect of the change in the σ my/△Kth,eff ratio on the ductility of the porous metal is greater than the effect of the change in the pore radius and fracture true strain. This model also shows it is possible to improve tensile ductility in porous metals by controlling the mechanical properties of the base metal or controlling the pore radius, in addition to reducing the pore volume fraction. In other words, increasing the ductility of the porous metal is possible by increasing the pore radius, or using a base metal with high yield strength and low σ my/△Kth,eff, or using a base metal with high fracture true strain. |
| Keywords:
theory and modeling, porous materials, tensile ductility, sintered iron, powder metallurgy processing |
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