直接壓出에 의한 Cu-Al 層狀 複合材料棒의 金屬 流動 特性
Metal Flow Characteristics of Copper Clad Aluminium Rods by the Direct Extrusion
x, 83 p.
직접압출 Cu-Al 층상 복합재료봉 금속유동;
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Copper clad aluminum composite material is formed with an aluminum core surrounded by copper sleeve. The laminated states of the two metals, with different mechanical properties, are extruded with bonded by pressure welding at the interface. The material has been proven to have high electro-conductivity and it is expected that the use of this material can substantially lower the cost of manufacturing, and therefore it has many applications as electro-conductive materials and in the production of micro light machines. Moreover, upon improvement of technology through extensive research and development, we would be able to considerably benefit from the export of this material. The research on the extrusion of copper clad aluminum composite material has mainly been done using the hydrostatic extrusion method. This method has been used because of the low friction between billet and the container greatly contributes in the reduction of friction effect, and compared with both direct and indirect extrusion methods, the hydrostatic method has been proven to have a lower extrusion pressure. While hydrostatic extrusion method has such superior process characteristics, it has some shortcomings in the production of copper clad aluminum. Comparing with other extrusion methods, direct extrusion is considered as easy to apply to industry fields, because of its possibilities of tandem extrusion, simple extrusion process and simplicity of shape of billet and structure of die. There are many variables of extrusion effected to sound clad extrusion which has no fracture with core and sleeve in the direct extrusion of copper clad aluminum composite material. Among these variables, extrusion ratio, semi-cone angle of die, extrusion temperature and extrusion speed are important factors effect to the direct extrusion of copper clad aluminum composite material. In order to analyze these variables that affect direct extrusion of copper clad aluminum composite material, extrusion carried out with extrusion ratio 2.78, 4.24, 6.25, 8.50, 12.25 and semi-cone angle of die 35 , 45 , 55 , 65 . Subsequently, by measuring before and after radius ratio of Cu sleeve and Al core, proportional flow state has been considered. And by measuring hardness, along extrusion way, variations of hardness has been discussed. This study presents about metal flow state and hardness changes as the effect of process parameter such as changes of extrusion ratio, semi-cone angle of die and extrusion temperature. As a result, this study suggest sound clad direct extrusion condition without any defect.