Investigation on the Size Effects of Polycrystalline Metallic Materials in Microscale Deformation Processes

미세성형 공정에서 다결정 금속재료의 크기효과에 관한 연구

  • Kim, Hong-Seok (Dept. of Mechanical Engineering, Seoul Nat'l Univ. of Technology) ;
  • Lee, Yong-Sung (Dept. of Mechanical Engineering, Seoul Nat'l Univ. of Technology)
  • 김홍석 (서울산업대학교 기계공학과) ;
  • 이용성 (서울산업대학교 기계공학과)
  • Received : 2010.05.10
  • Accepted : 2010.06.01
  • Published : 2010.10.01


Microforming, which exploits the advantages of metal forming technology, appears very promising in manufacturing microparts since it enables the production of parts using various materials at a high production rate, it has high material utilization efficiency, and it facilitates the production of parts with excellent mechanical properties. However, the conventional macroscale forming process cannot be simply scaled down to the micro-scale process on the basis of the extensive results and know-how on the macroscale process. This is because a so-called "size effect" occurs as the part size decreases to the microscale. In this paper, we attempt to develop an effective analytical and experimental modeling technique for explaining the effects of the grain size and the specimen size on the behavior of metals in microscale deformation processes. Copper sheet specimens of different thicknesses were prepared and heat-treated to obtain various grain sizes for the experiments. Tensile tests were conducted to investigate the influence of specimen thickness and grain size on the flow stress of the material. In addition, an analytical model was developed on the basis of phenomenological experimental findings to quantify the effects of the grain size and the specimen size on the flow stress of the material in microscale and macroscale forming.


Microforming;Size Effect;Flow Stress;Polycrystalline Material


Supported by : 한국연구재단


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