Development of High-Strength and High-Conductivity Copper Alloys

• Main Authors: Huang, Ji Rong, 黃紀蓉
• Other Authors: Yeh, Jien Wei
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/mgtw2g

碩士 === 國立清華大學 === 材料科學工程學系 === 103 === From our previous study, the muti-component Cu88 alloy has higher peak hardness than Cu89 alloy when aged at 450°C. It indicates that small amount of multi-elements can increase hardness and electrical conductivity. However, it is difficult to achieve an excellent combination of hardness and electrical conductivity, compared with toxic and expensive Cu-Be alloy. The present study is to improve hardness and electrical conductivity by adding more different kinds of alloy element, such as Nb and C. Through muti-component competition during precipitation hardening, high-strength and high-conductivity of copper alloys are expected to be achieved. In Cu88 alloy series, this study investigates the effect of Al content on hardness and electrical conductivity properties. Cu88Al1 alloy has the best performance in hardness and conductivity, i.e. 307 HV and 30.7 %IACS. Furthermore, Cu88Al1.5V0.1C0 is improved by reducing the content of V and C element. The results show that a higher electrical conductivity of 32.0 %IACS than Cu88Al1.5 is obtained without 80 % cold work. In Cu98 alloy series, the Cu98V0.3 alloy aged at 450°C for 50 h has a hardness of 165 HV and an electrical conductivity of 78.4 %IACS, while Cu98V0.15 alloy exhibits 182 HV and 75.5 %IACS. Both of them have good combination of mechanical/electrical properties. The newly-developed Cu88 alloy series don’t soften when aged at 450°C even up to 50 h, while Cu-Be alloy softens at 400°C-aging only for 1h. Cu88 alloy series also have better wear resistance and softening resistance as compared with commercial Cu-Be alloy. Thus, Cu88 alloy has the potential to replace commercial Cu-Be alloy. Furthermore, the newly-developed Cu98 alloy series have better hardness and electrical conductivity as compared with commercial Cu-Sn contact wire material ( >125 HV, >72% IACS). Cu98V0.15 alloy has the best combination of hardness and electrical conductivity, i.e. 182 HV and 75.5 %IACS. In addition, it displays good wear and softening resistances. Therefore, new Cu98 alloy has the promising potential in contact wires used for high-speed electrified railway and lead-frames used in IC package.