Abstract:
본 발명은 서로 다른 2종 이상의 금속편을 원주방향으로 번갈아 배치한 후 압축비틀림 공정을 통해 재료에 원주방향의 소성변형을 가하여 층과 층 사이에서 좋은 금속결합을 갖도록 하고, 동시에 복합화 과정에서 큰 전단변형이 가해져 재료의 결정립 미세화를 통해 재료의 강도, 경도, 내마모성 등의 기계적 물성을 향상시킬 수 있는 새로운 조직구조를 갖는 복합재료의 제조방법에 관한 것이다. 본 발명에 따른 복합재료의 제조방법은, (a) 2종 이상의 서로 다른 금속재료로 이루어진 단위 금속편을 준비하는 단계; (b) 상기 2종 이상의 단위 금속편을 상,하부 다이가 구비된 금형에 원주방향으로 배치하는 단계; (c) 장입된 금속편에 상,하부 다이를 이용하여 압축응력을 가하는 단계; 및 (d) 가압된 상태에서, 상기 상,하부 다이 중 일방 또는 양방을 회전시켜 회전력을 가하는 단계;를 포함한다.
Abstract:
PURPOSE: A manufacturing method of a spiral shape layered composite material using compression torsion is provided to obtain composite materials including excellent interface coherence through a simple method in which a piece of unit metal pieces is mounted on a mold and is pressurized. CONSTITUTION: Unit metal pieces comprised of different kinds of metal materials are prepared. The unit metal pieces are arranged at a mold including an upper die and a lower die in a circumference direction. The metal pieces are pressurized by the upper die and the lower die. Rotatory power is applied by rotating the upper die and the lower die in the pressurized state.
Abstract:
The present invention relates to a method for evaluating bonding properties of a multi-layered metal plate using a digital image interpretation technique and, more particularly, to a method for evaluating interface bonding properties in a tension test which is a method for evaluating mechanical properties of a general metal specimen and is simpler than the conventional methods for evaluating interface bonding properties. In addition, through digital image analysis, the existence of interface bonding can be determined by analyzing the distance between layers, a local deformation rate, etc. The analysis on a bonding property can become easy through the relationship with a transformation rate-stress curve, which is a general property of a material and is obtained from a tension test. A method for analyzing interface bonding properties prepared by the present invention comprises the following steps of: (a) realizing a random pattern on a side of a specimen; (b) obtaining an image of the side of the specimen through an in-situ or an ex-situ test simultaneously with a tension test; (c) observing interface properties through digital image interpretation.
Abstract:
PURPOSE: A torsion severe plastic deformation method of conical metal tube is provided to make a micro-structure to microcrystalline or nano-crystalline, thereby improving the mechanical property of conical metal tube. CONSTITUTION: A torsion severe plastic deformation method of conical metal tube performs the following steps. A punch suitable for the inner shape of the conical metal pipe is mounted in the inside of conical metal pipe. A mold suitable for the outer shape of the conical metal pipe is mounted in the outside of conical metal pipe. A micro-structure of conical metal pipe is formed into microcrystalline or nano-crystalline through the shear deformation obtained by applying the compression and torsion to the conical metal pipe by means of the punch and the mold. The shear deformation is obtained by rotating the punch after the punch is pressured by the mold. [Reference numerals] (AA) Initial piece shape; (BB) After process piece shape; (CC) Piece input step; (DD) Mold insertion step; (EE) Twisting; (FF) Compression and twisting step; (GG) Compression strength