毛细铜/钛复合管材的游动芯头拉拔制备及组织性能

在热旋制备界面结合质量优异的铜/钛双金属复合管坯的基础上，对复合管进行了游动芯头拉拔加工，重点研究了复合管材游动芯头拉拔加工成形能力以及拉拔加工对复合管材组织性能的影响.研究结果表明，游动芯头拉拔方式，特别是减壁拉拔，对铜/钛复合管材结合界面有较大的破坏作用，且难以实现多道次连续拉拔加工，单道次拉拔加工量不宜超过30%；575℃保温70 min的道次间退火虽然对界面元素扩散情况影响不大，但能缓解加工硬化和残余应力，使得铜/钛复合管材的平均剥离强度由变形态的7.8 N·mm-1提高到退火态的17.1 N·mm-1，大幅度提高铜/钛复合管材的后续拉拔加工性能.通过严格控制拉拔减壁量，合理制定了铜/钛复合管材的拉拔加工工艺，成功制备了结合性能优异的毛细规格铜/钛复合管材. 

Preparation of the capillary copper/titanium composite pipe by floating-plug drawing processing and its microstructure and properties

A copper/titanium bimetallic composite pipe with high interfacial bonding quality was manufactured by the high-temperature rotary swaging forming, and then was processed by the floating-plug drawing process. The forming ability of drawing process and the effect of drawing process on the microstructure and properties of the product were mainly investigated. The results show that the floating plug drawing, especially the wall-reduction drawing, has a great destructive effect on the bonding interface of the pipe, which results in that it is difficult to carry out multi-pass continuous drawing, and single pass drawing volume should not reach over 30%. The annealing at 575℃ for 70 min has little effect on the diffusion of interfacial elements, but it can reduce the work hardening and residual stress. This process makes the pipe's average peel strength increase from 7. 8 N·mm-1 (worked state) to 17. 1 N·mm-1 (annealed state), which considerably improves the subsequent drawing performance of the pipe. A reasonable drawing forming process for the copper/titanium composite pipe was made based on the strict control of drawing wall-reduction, and a capillary size pipe with an excellent bonding property was successfully prepared.