Transactions of Materials and Heat Treatment

Title：Drawing process and evolution of microstructure and properties for heat pipe of ultra-thin and super-fine in smartphone

Authors： Chen Yan Xiao Qiaoping Li Kun You Jing Wang Songwei Zhang Shihong

Unit： Jiangxi Copper Corporation Limited Jiangxi Copper Technology Institute Co. Ltd. Institute of Metal Research Chinese Academy of Sciences

KeyWords： heat pipe in smartphone oxygen-free copper drawing process microstructure evolution mechanical property electrical conductivity

ClassificationCode：TG146.1

year,vol(issue):pagenumber：2022,47(8):111-117

Abstract：

The oxygen-free copper heat pipes of ultra-thin and super-fine in the smartphone were drawn by a hydraulic drawing machine with a floating plug, and the influence of drawing process on pipe breakage during the drawing process was studied. Then, the microstructure evolution of grains in copper pipe and the changes of mechanical and electrical conductivity properties during the drawing process were observed. The results show that the oxygen-free copper pipe is drawn by the floating plug in multiple passes, the grains tend to be fibrous along the drawing direction, and the tensile strength and Vickers hardness are continuously improved, but the influence of drawing deformation on the electrical conductivity is relatively small. When the cumulative deformation amount of the oxygen-free copper pipe reaches 75.8%, the tensile strength of the copper pipe is 416.5 MPa, and the problem of pipe breakage is easy to occur if continuing to draw, so the intermediate annealing is required. After deformation of eight drawing passes and one intermediate annealing treatment, the heat pipe of ultra-thin and super-fine in the smartphone with specification of Φ2 mm×0.08 mm is obtained with the tensile strength of 403.8 MPa, the elongation of 1.78%, the electrical conductivity of 98.85%IACS, the outer diameter tolerance of ±0.02 mm and the wall thickness tolerance of ±0.01 mm.

Funds：

中国博士后科学基金资助项目（2019M662276）；中国科学院科技服务网络计划区域重点资助项目（KFJ-STS-QYZD-145）；江西省重大科技研发专项（20203ABC28W004）

陈岩（1984-），男，博士，副研究员，E-mail：ychen10b@126.com

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