双金属管变形升温轧制复合机制研究

Depending on bonding criteria of interface, rolling bonding mechanisms of copper/aluminum pipe by self heating during plastic deformation will be carried out in this project. By taking copper T2/aluminum alloy 3003 as research object, key physical parameters affecting the nature of interface bonding of cladding pipe during three-roll planetary rolling process will be first analyzed and epurated, of whose optimal parameters scope is set up for temperature field simulation. By using Thermal Simulator Experimental for offline deformation at high strain rate, the constitutive relationship and processing maps of copper/aluminum will be obtained by means of detailed designing, such as three compression routes with single, double and three passes and several temperature rising modes. Meanwhile coordinated deformation conditions of copper and aluminium during rolling bonding will be established. Mechanisms of mutual diffusion for interface atoms and recrystalization model will be drawn accordingly from microstructural characterization, interfacial strength test and hardness test combined with above processing maps . Explore the bonding criteria for interfacial atoms in rolling by self heating during plastic deformation and obtain the mechanisms of interface bonding overall. Above results may accordingly enlargen the research connotation of basic theory for solid-solid pressure bonding and techniques for metals, provide fundamental data for controlling the expected bonding microstructure and bonding quality, in which has important significance in accelerating technology progress and advancing the metallurgical bonding mechanisms of bi-metal cladding during rolling bond by self heating during plastic deformation towards nuclear and pipe transportation industry use.

围绕界面结合判据开展双金属变形升温轧制复合机制的研究。以T2紫铜/3003铝合金为研究对象，提炼影响复合管三辊行星轧制过程界面结合的关键物理量及参数范围；设计单、双、三道次复合压缩与多路径升温等实验方案，采用离线高速大变形物理模拟，获得双金属的本构关系与加工图，确定双金属协调变形条件；通过微观组织表征、界面强度与硬度检测，构建多重因素作用下界面金属原子互扩散、再结晶模型，获得铜铝管变形升温热加工界面结合规律，提出界面复合判据，最终建立具有普适性的变形升温热加工双金属复合加工窗口。预期研究结果可用于丰富固相双金属复合理论与方法的研究内涵，推动变形升温热加工双金属材料向核工业、管道运输等领域的应用有重要的指导意义。

本项目中的变形升温热加工所需的温度条件靠塑性加工的变形热来实现，其典型范例为三辊行星轧制技术。围绕双金属复合管两侧界面结合判据开展双金属变形升温轧制复合机制的研究。选用T2铜、3003铝合金及ACC复合管为研究对象，通过提炼影响复合管三辊行星轧制过程界面结合的关键物理量及参数范围，构建了三辊行星轧制变形区解析模型，获得了轧入线和轧出线的计算方程及沿轧辊轴向的实际分布。设计Gleeble离线物理模拟实验，对T2铜、3003铝进行了热压缩实验，采用Arrhenius及Z参数模型，建立两金属的本构方程，同时采用动态材料模型理论(DMM)建立该合金在不同应变量下的加工图，确定了双金属协调变形条件。离线物理模拟实验中，3003铝与T2铜动态再结晶现象分别出现在673K与293-723K范围，铜在高于723K范围时出现动态回复现象，组织不均匀。成品ACC螺纹管的界面结合为冶金结合，两界面结合紧密，无微观尺度上的孔隙，同时界面结合处也未检测到CuAl2等金属间化合物的存在，而停机取样制备的ACC复合管表观应变60%~90%硬度一致性得以保持，~60%之前以铝层变形为主，~60%之后以铜层变形为主，界面附近金属均未发生再结晶。基于组织演变规律与加工图，构建双金属管变形升温轧制复合过程的稳态加工窗口.引入了新的高压切变变形方法，将劈尖原理应用于高压管材切变法制备出铜/铝复合管，获得良好的冶金结合界面，为将界面复合规律的研究延伸到梯度材料、纳米晶领域打下了基础。项目完成了预期目标，期间共发表论文4篇，接收论文2篇，在投论文2篇，其中SCI收录2篇，EI收录3篇，申请发明专利7项，在本研究方向上培养硕士研究生4名（已毕业）。