Transactions of Nonferrous Metals Society of China
中國有色金屬學會學報

Effects of annealing process on electrical conductivity and mechanical property of $Cu - Te$ alloys
退火工藝對 $Cu - Te$ 合金導電性和力學性能的影響

ZHU Da－chuan（朱达川） $^{1}$ ，TANG Ke（唐科） $^{2}$ ，SONG Ming－zhao（宋明昭） $^{1}$ ，TU Ming－jing（涂铭旌） $^{1}$
ZHU Da-chuan（朱達川） $^{1}$ ，TANG Ke（唐科） $^{2}$ ，SONG Ming-zhao（宋明昭） $^{1}$ ，TU Ming-jing（塗銘旌） $^{1}$ 1．College of Materials Science and Engineering，Sichuan University，Chengdu 610065，China；
1.四川大學材料科學與工程學院，四川成都 610065;2．College of Information Engineering，Chengdu Univesity of Technology，Chengdu 610059，China
2.成都理工大學資訊工程學院，四川成都 610059

Received 13 June 2005；accepted 5 December 2005
2005年6月13日接收;2005年12月5日接收

Abstract 抽象

The effects of annealing process on the electrical conductivity and mechanical properties of $Cu - Te$ alloys were studied via AG－10TA electronic universal machine，SB2230 digital electric bridge，SEM and EDS．The results show that recrystallization and precipitation occur simultaneously during the annealing process of $Cu - Te$ alloys．Tellurium precipitates as ${Cu}_{2} Te$ second phase．The grain size increases with the increasing of annealing temperature and time．The electrical conductivity increases monotonously．The tensile strength of $Cu - Te$ alloy is higher than that of pure copper．
通過 AG-10TA 電子萬能機、SB2230 數字電橋、SEM 和 EDS 研究了退火工藝對合金電 $Cu - Te$ 導率和力學性能的影響，結果表明， $Cu - Te$ 在合金退火過程中，再結晶和析出同時發生。 ${Cu}_{2} Te$ 第二相，晶粒尺寸隨退火溫度和時間的增加而增大，電導率單調增加，合金的 $Cu - Te$ 抗拉強度高於純銅。

Key words：

Cu - Te

alloys；

{Cu}_{2} Te

；electrical conductivity；mechanical property；annealing；recrystallization；precipitation
關鍵詞：

Cu - Te

合金;

{Cu}_{2} Te

電導率;機械性能;退火;再結晶;沉澱

1 Introduction 1 引言

Pure copper and copper alloys are widely used due to the high electrical conductivity，high heat transfer， corrosion resistance and excellent formability［1－5］．But the strength of pure copper is low and the strength gained during cold working will decrease quickly after annealing．So developing copper alloys，which not only have high strength，but also keep high electrical conductivity simultaneously，is necessary［6－10］． However，high strength and high conductivity are a contradiction for copper alloys．So the principle to develop high conductivity and high strength copper alloys is adding low－solubility elements to pure copper， forming super－saturation solid solution，and then making added elements precipitate as the second phases after annealing．Consequently，the electrical conductivity improves quickly and the strength of alloys is still high［11，12］．Presently most researches are concentrated on

Cu - Cr, Cu - Fe

and so on，while the studies on

Cu - Te

alloys are limited［13－15］．The prior research showed that the electrical conductivity of

Cu - Te

alloys can reach

94 % - 103 %

IACS and

Cu - Te

alloys have special properties，such as anti－electric corrosion，arc－
純銅和銅合金因其高導電性、高傳熱性、耐腐蝕性和優異的成型性而被廣泛應用[1-5]，但純銅的強度較低，annealing.So 發展銅合金后，其強度會迅速降低，銅合金不僅具有高強度，而且同時保持高導電性是必要的[6-10]。然而，高強度和高導電性是銅的一個矛盾開發高導電率、高強度銅合金的原理是將低溶解度元素添加到純銅中，形成過飽和固溶體，然後使添加的元素在退火后沉澱為第二相，因此，電導率迅速提高，合金的強度仍然很高[11,12]，目前大多數研究集中在

Cu - Cr, Cu - Fe

等方面，而對

Cu - Te

alloys.So 以往的研究表明，合金的

Cu - Te

電導率可以達到

94 % - 103 %

IACS，並且

Cu - Te

合金具有特殊性能，如抗電腐蝕、電弧腐蝕、電弧腐蝕
extinguishing synchronously［16，17］．In order to get high strength and high electrical conductivity，exploring the annealing process is necessary．So the influence of interaction between precipitation and recrystallization of

Cu - Te

alloys during annealing process on their electrical conductivity and mechanical property is investigated in this paper．
為了獲得高強度和高導電性[16,17]，本文探討了

Cu - Te

退火過程中合金在退火過程中析出和再結晶的相互作用對合金導電性和力學性能的影響，探討了退火 necessary.So 過程。

2 Experimental 2 實驗

Cu - Te

alloys were melted in a

ZG - 25 A

vacuum induction furnace by adding different amounts of pure tellurium to industrial copper in an argon protective atmosphere．Tellurium content at different areas of

Cu - Te

alloy ingots was detected by ICAP9000（N＋M）plasma spectrum．The nominal composition of Te is shown in Table 1．Then the ingots were forged and hot－rolled to copper stick with diameter of 8 mm and the copper sticks were cold drawn to wires with diameter of 2 mm ．At last， the copper wires were annealed in the vacuum resistance furnace．The tensile strength was measured by AG－10TA electronic universal machine．The electrical conductivity was measured by SB2230 digital electric bridge and the microstructure was investigated by JSM－5900LV scanning electronic microscope．

Cu - Te

在

ZG - 25 A

真空感應爐中，在氬氣保護氣氛中，向工業銅中加入不同量的純碲，使合金錠不同區域的

Cu - Te

碲含量採用 ICAP9000（N+M）等離子體光譜測定，Te 的公稱組成見表 1，然後將錠鍛造並熱軋成直徑為 8 mm 的銅棒，將銅棒冷拔成直徑為 2 mm 的線材。最後，在真空電阻爐中對銅線進行退火，用 AG-10TA 電子萬能機測量抗拉強度，用 SB2230 數字電橋測量電導率，用 JSM-5900LV 掃描電子顯微鏡研究其微觀組織。

Table 1 Nominal composition and measured composition of Te in

Cu - Te

alloys (mass fraction, %)
表 1 合金中

Cu - Te

Te 的標稱成分和實測成分（品質分數，%）

Sample No. 樣品編號	Nominal 名義	Measured 量過的
1	0	0
2	0.20	0.19
3	0.35	0.32
4	0.50	0.39

3 Results 3 結果

3.1 Effect of annealing temperature on electrical
3.1 退火溫度對電氣的影響

conductivity and tensile strength of

Cu - Te

alloy wires
合金絲的

Cu - Te

導電性和抗拉強度

Figs. 1 and 2 present the effects of annealing temperature on the electrical conductivity and tensile strength of

Cu - Te

alloy wires after annealing for 2 h .
圖 1 和圖 2 顯示了退火溫度對

Cu - Te

退火 2 h 後合金絲導電率和抗拉強度的影響。

Fig. 1 Effect of annealing temperature on electrical conductivity of

Cu - Te

alloys
圖 1 退火溫度對

Cu - Te

合金電導率的影響

Fig. 2 Effect of annealing temperature on tensile strength of

Cu - Te

alloys
圖 2 退火溫度對

Cu - Te

合金拉伸強度的影響

It can be seen from Figs. 1 and 2 that with the annealing temperature increasing, the electrical conductivity increases monotonously, while the tensile strength of

Cu - Te

alloys wire firstly decreases and finally
從圖 1 和圖 2 中可以看出，隨著退火溫度的升高，電導率單調增加，而合金絲的

Cu - Te

抗拉強度先降低，最後
fluctuates within small range.
在較小範圍內波動。

3.2 Effect of annealing time on electrical conductivity and tensile strength of $Cu - Te$ alloy wires
3.2 退火時間對合金絲導電 $Cu - Te$ 性和抗拉強度的影響

The variations in electrical conductivity and tensile strength of

Cu - Te

alloy wires after annealing at

420^{\circ} C

for different times are shown in Figs. 3 and 4, respectively.

Cu - Te

合金絲退火

420^{\circ} C

后在不同時間的電導率和抗拉強度的變化分別如圖 3 和圖 4 所示。

Fig. 3 Effect of annealing time on electrical conductivity of

Cu - Te

alloys at

420^{\circ} C

圖 3 退火時間對

Cu - Te

合金

420^{\circ} C

電導率的影響

Fig. 4 Effect of annealing time on tensile strength of

Cu - Te

alloys at

420^{\circ} C

圖 4 退火時間對

Cu - Te

合金

420^{\circ} C

抗拉強度的影響

As can be seen from Fig.3, with the extended time, the electrical conductivity of

Cu - Te

alloy wires exhibits consistent climb tendency. But a turning point appears in Fig. 4.
從圖 3 中可以看出，隨著時間的延長，合金絲的

Cu - Te

電導率表現出一致的爬升趨勢。但圖 4 中出現了一個轉捩點。

3.3 Effect of annealing process on microstructure of Cu -Te alloys
3.3 退火工藝對 Cu -Te 合金微觀組織的影響

The microstructures of sample 3 in cast, hot- rolled, and cold-drawn state and annealed at different temperatures for 2 h were observed by XJP-6 metallograph, which are shown in Fig. 5.
用 XJP-6 金相法觀察樣品 3 在鑄造、熱軋和冷拔狀態下在不同溫度下退火 2 h 的顯微組織，如圖 5 所示。

It can be confirmed that the recrystallization happens after annealing at

390^{\circ} C

for 2 h , but recrystal-
可以確認，再結晶發生在退

390^{\circ} C

火 2 h 後，但重結晶-

Fig. 5 Effect of annealing temperature on microstructure of sample 3: (a) Cast; (b) Hot-rolled; © Cold drawn; (d) Annealed at

390^{\circ} C

for 2 h ; (e) Annealed at

420^{\circ} C

for 2 h ; (f) Annealed at

450^{\circ} C

390^{\circ} C

2 小時;（e）退火

420^{\circ} C

2 小時;（f）退火

450^{\circ} C

2 小時
lization is incomplete. With the increasing temperature, the recrystallization process finishs and grains start to grow up.
lization 不完整。隨著溫度的升高，再結晶過程結束，晶粒開始生長。

Fig. 6 shows the microstructures of sample 3 after annealing at

420^{\circ} C

for 2 h and 6 h . It can be seen that prolonging annealing time makes grain grow up.
圖 6 顯示了樣品 3 退火

420^{\circ} C

2 h 和 6 h 後的微觀結構。由此可見，延長退火時間會使晶粒長大。

To ascertain the composition of precipitation, the engery dispersive spectrum (EDS) analysis were conducted on sample 3 after annealing at

420^{\circ} C

for 6 h . Combining the EDS results with

Cu - Te

alloy phase diagram, the precipitation is determined to be

{Cu}_{2} Te

.
為了確定沉澱物的組成，在退火

420^{\circ} C

6 h 後對樣品 3 進行了能量色散譜（EDS）分析。將 EDS 結果與

Cu - Te

合金相圖相結合，確定析出值為

{Cu}_{2} Te

。

4 Discussion 4 討論

The main reason for the above changes lies on that recrystallization and precipitation happen in

Cu - Te

alloys simultaneously during annealing process. Firstly, trace tellurium dissolved in copper can improve the recrystallization temperature of copper because solute atoms can decrease the nucleation rate and growth rate of
上述變化的主要原因在於

Cu - Te

合金在退火過程中同時發生再結晶和沉澱。首先，溶於銅中的痕量碲可以提高銅的再結晶溫度，因為溶質原子可以降低銅的成核速率和生長速率。

Fig. 6 SEM morphologies of sample 3 after annealing at

420^{\circ} C

for different times: (a) 2 h ; (b) 6 h
圖 6 樣品 3 在不同

420^{\circ} C

退火時間下的 SEM 形貌：（a） 2 h;（b） 6 小時

Foundation item：Project（50201010）supported by the National Natural Science Foundation of China；Project（20010610013）supported by Dectoral Subject Foundation of Ministry of Eduction
基金專案：國家自然科學基金面上專案（50201010）;教育部學科基金專案（20010610013）
Corresponding author：ZHU Da－chuan；Tel：＋86－28－85460830；Fax：＋86－28－85460982；E－mail：zdc89＠163．com
通訊作者：朱 Da-chuan;Tel:+86-28-85460830;Fax:+86-28-85460982;E-mail:zdc89@163.com

Effects of annealing process on electrical conductivity and mechanical property of Cu − Te Cu − Te Cu-Te\mathrm{Cu}-\mathrm{Te} alloys 退火工藝對 Cu − Te Cu − Te Cu-Te\mathrm{Cu}-\mathrm{Te} 合金導電性和力學性能的影響