基于局部强应力作用波平轧制（CFR）钛/钢复合板成形机制及复合机理

The titanium/steel composite plate combines the good mechanical properties of steel and the excellent corrosion resistance of titanium. At the same time, it can reduce the material cost and gradually become a substitute for single titanium. It is widely used in petroleum, chemical industry, especially marine engineering. Aiming at the problems of many interfacial brittle compounds, high residual stress and low bonding strength existing in the traditional preparation methods of titanium/steel composite plate, this project proposes a warm rolling preparation method of titanium/steel composite plate based on local strong stress--Corrugated Flat Rolling(CFR), which aims at forming stress peaks, promote deformation coordination, and reduce rolling temperatures by asymmetric pressing of corrugated rolls and flat rolls. Through theoretical analysis, rolling experiment, microscopic characterization and other comprehensive research, a high-precision dynamic composite numerical simulation model of titanium/steel composite plate CFR process based on metallurgical bonding criterion is established to clarify the local strong stress space-time state and bimetal deformation coordination mechanism of titanium/steel composite plate in corrugated roll gap, explore the influence of rolling and annealing processes on grain size, element diffusion, compound production and metallurgical bonding, master the intrinsic relationship between the microstructure evolution of composite plate interface and bonding strength and mechanical properties, reveal the high-strength composite mechanism of titanium and steel by CFR.

钛/钢复合板兼具金属钢良好的力学性能及金属钛优异的耐腐蚀性，同时可以降低材料成本，逐渐成为单一钛材的替代品，广泛应用于石油、化工尤其是海洋工程等领域。本项目针对钛/钢复合板传统制备方法存在的界面脆性化合物多、残余应力大、结合强度低等问题，提出一种基于局部强应力作用的钛/钢复合板温轧制备方法——波平轧制(Corrugated Flat Rolling—CFR)，旨在通过波纹辊与平辊的非对称压下，形成应力峰值、促进变形协调、降低轧制温度。通过理论分析、轧制试验、微观表征等综合研究，建立基于钛钢双金属冶金结合判据的轧制过程高精度动态复合模拟模型，明晰钛/钢复合板在波纹辊缝中的局部强应力时空变化状态和双金属变形协调机制；探索轧制及退火过程对晶粒尺寸、元素扩散、化合物生成及冶金结合的影响规律，掌握复合板层界面组织演变与结合强度、力学性能之间的内在联系，揭示钛钢两金属波平轧制高强度复合机理。

钛/钢复合板兼具钛的高耐腐蚀性和钢的优良结构性，同时降低了钛材使用成本，目前广泛应用于化工、电力、石油、海洋等各个重要领域。由于钛、钢两种金属热物性差异大，界面连接存在易氧化、易生成脆性化合物等不利于结合的情况。目前钛/钢复合板大多采用爆炸或轧制制备，但现有方法仍存在结合强度低，环境污染大等缺陷。针对此，本文针对传统钛/钢复合板轧制复合技术，提出了一种利用波纹辊轧制钛/钢复合板的新技术，旨在通过周期连续的波纹辊外形对难变形金属产生局部强应力作用，以制备出高界面结合强度、波纹形界面、综合性能良好的钛/钢复合板。通过调整工艺参数，得到了界面波纹状、板形良好的钛/钢双层复合板，界面结合强度超过300 MPa，远超国标53%，拉剪断裂位置由界面转向钛基体。此外，开发了钛/钢双层组坯轧制复合工艺，得到的双层组坯焊缝没有缺陷，满足了后续轧制需求。研究了钛/钢复合板脉冲电流辅助退火工艺，结果表明，电流作用明显提高了退火效率。本项目开展相关实验研究、数值模拟研究与性能表征分析，阐明界了钛/钢界面结合机理，为高强冶金结合钛/钢复合板的界面组织调控以及工艺参数的优化提供理论指导和实验依据。