高強度高導電銅合金之開發

Development of High-Strength and High-Conductivity Copper Alloys

黃紀蓉(Huang, Ji Rong)

指導教授 ： 葉均蔚

國立清華大學/工學院/材料科學工程學系/碩士(2015年)

摘要

本實驗室開發的Cu88多元微量合金於450°C時效時產生顯著的時效硬化現象，硬度可達301 HV，而非多元微量添加之Cu89只有264 HV，而在時效硬化量上Cu88較Cu89高出許多，顯示微量添加對合金之硬度及時效硬化量造成顯著的提升，但硬度及導電率綜合性質仍難與昂貴有毒的Cu-Be合金競爭。因此本論文為增強合金析出硬化並同時提升導電率，以更多元微量添加低固溶度的合金元素的方式，如C、Nb，使經由多元競爭及析出強化，提升銅合金的強度及導電率。另外以此想法為基礎，開發高強度高導電高銅含量之Cu98合金，目標為硬度>166 HV、導電率>75 %IACS。
在Cu88合金系列中，針對Al變量對合金硬度及導電率表現進行研究，其中Cu88Al1合金有最佳之綜合表現，其尖峰硬度為287 HV，導電率為31.9 %IACS。經冷加工後時效處理，此合金硬度可達到307 HV，而導電率些微下降到30.7 %IACS。由SEM微結構觀察，析出物為兩種多元混合相，富鎳矽相及富鎳矽鉻釩相，使產生顯著的析出硬化效果。於Cu88合金系列中，將Cu88Al1.5做進一步的改良，V減量並去除C得到Cu88Al1.5V0.1C0合金，析出物為富鎳矽相及富鎳矽鈮相，硬度與Cu88Al1.5合金相似，但是在未滾軋時的導電性可達32.0 %IACS。
在Cu98合金系列中，針對V變量對合金硬度及導電率表現進行研究，以減V後之Cu98V0.15有最佳之綜合表現，冷滾軋再時效處理之硬度達182 HV，而導電率達75.5 %IACS，由SEM微結構觀察，析出物為兩種多元混合相，富矽鉻釩相及富矽鈮相，使產生顯著的析出硬化效果。
應用性質方面，新開發的Cu88合金系列相較於商用銅鈹合金具有較良好的抗高溫軟化能力，經450°C 50小時仍未出現時效軟化，而銅鈹合金經400°C 1小時即出現明顯的過時效軟化。此外新開發之Cu88合金也多具備優異的抗磨耗性質，其硬度及導電率綜合性能可取代Cu-Be合金。新開發之Cu98合金系列相較於法國的Cu-Sn合金鐵路接觸線( >125 HV及 >72% IACS)，Cu98V0.3合金硬度為165 HV、導電率為78.4 ％IACS，Cu98V0.15合金有更佳的硬度為182 HV，且導電性為75.5 ％IACS，皆具有優越的表現，同時也達到開發目標(>166 HV及 >75 %IACS)。此外，新開發之Cu98合金也具備優異的抗磨耗性質，因此對於鐵路接觸線及引線框架材料的應用極具潛力。

關鍵字

銅合金

並列摘要

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.

參考文獻

[30] 第一伸銅科技股份有限公司, http://www.fcht.com.tw/cmainpage.htm.

[3] C. W. Tsai, M. H. Tsai, J. W. Yeh, and C. C. Yang, "Effect of temperature on mechanical properties of Al0.5CoCrCuFeNi wrought alloy," Journal of Alloys and Compounds, vol. 490, pp. 160-165, Feb 2010.

[6] 邱文芳, "取代Cu-Be合金之無鈹銅合金開發," 國立清華大學材料科學工程研究所碩士論文, 2014.

[12] V. A. Phillips and L. E. Tanner, "High resolution electron microscope observations on G.P. zones in an aged Cu-1.97wt.% Be crystal," Acta Metallurgica, vol. 21, pp. 441-448, Apr 1973.

[14] B. Djuric, M. Jovanovic, and D. Drobnjak, "A Study of Precipitation in Cu-Be Alloys," Metallography, vol. 13, pp. 235-247, 1980.