(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083；
2. 中南大學(xué) 有色金屬材料科學(xué)與工程教育部重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083；
3. 河南科技大學(xué) 材料科學(xué)與工程學(xué)院，洛陽(yáng) 471023；
4. 浙江天寧合金材料有限公司，金華 321002；
5. 深圳市中金嶺南有色金屬股份有限公司，深圳 518040)
摘 要: 采用下引連鑄工藝制備了d 11 mm Cu-4%Ag合金棒坯，棒坯具有高軸向取向柱狀晶組織，表面質(zhì)量良好，斷后伸長(zhǎng)率達(dá)到35.0%，可直接進(jìn)行拉拔加工成d 0.04 mm微細(xì)絲，無(wú)中間退火的累積冷變形量達(dá)99.998%。拉拔過(guò)程中，在一般變形階段，棒材變形機(jī)制為位錯(cuò)滑移，形成了較多的位錯(cuò)胞，晶內(nèi)發(fā)生微區(qū)晶體轉(zhuǎn)動(dòng)，隨應(yīng)變量增大，剪切變形程度加劇，晶內(nèi)形成了較多的切變帶；在大變形階段，通過(guò)各種動(dòng)態(tài)回復(fù)機(jī)制如納米孿晶、位錯(cuò)墻的亞晶化，層狀界面，實(shí)現(xiàn)大塑性變形。隨著變形量的增加，棒材的抗拉強(qiáng)度和硬度分別由鑄態(tài)的245 MPa和63.4 HV增加至變形量99.7%時(shí)的655 MPa和187 HV，而導(dǎo)電率由90.3% IACS則降低至82.2% IACS。上述下引連鑄-連續(xù)拉拔加工方式制備Cu-Ag合金微細(xì)絲材具有短流程、高效率的優(yōu)勢(shì)，提供了新的思路。
關(guān)鍵字: Cu-Ag合金；下引連鑄；定向凝固；拉拔；力學(xué)性能
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China;
3. School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023
4. Zhejiang Tianning Alloy Material Co., Ltd., Jinhua 321002, China；
5. Shenzhen Zhongjin Lingnan Nonfemet Co., Ltd., Shenzhen 518040, China）
Abstract:A d 40 μm Cu-4%Ag alloy wire with high strength and high electrical conductivity was prepared by continuously directional solidification and cold drawing. The evolutions of microstructure and properties were investigated by means of optical microscope observation, electron microscopes observation, hardness test, tensile test, and electrical conductivity measurement. The results show that the continuous columnar grain structure uniformly distributes along the solidification direction in the as-cast alloy. The drawing process is divided into different stages, corresponding to the main deformation mechanism of the dislocation slip and twinning, the microcrystalline rotation, the dynamic recovery, the evolution of layered interface, and partial dynamic recrystallization. After the deformation with the area reduction ratio of 99.7%, the tensile strength, hardness and electrical conductivity of the alloys are 655 MPa, 187 HV and 82.2%IACS, respectively.
Key words: Cu-Ag alloy; downward continuous casting; directional solidification; drawing; mechanical properties
