钛/不锈钢电致塑性轧制复合机理研究

Titanium/stainless steel composite plate is an ideal material for corrosion-resistant environmental equipment manufacturing and has a broad application prospect. However, due to the mechanical properties of titanium and stainless steel are quite different, the phenomenon of uncoordinated deformation prone to occur during the rolling bonding. When the heating temperature is relatively high, the composite interface is prone to form brittle intermetallic compounds, which seriously restricts the production of titanium/stainless steel composite plates. This project aims at the existing problems of titanium/stainless steel rolling bonding, and puts forward a process method based on pulse current assisted titanium/stainless steel rolling bonding. The influence of process parameters on the coordinated deformation of titanium/stainless steel during electroplastic rolling process is studied by finite element simulation and rolling composite experiment, and the deformation mechanism of titanium/stainless steel electroplastic rolling is established. On the basis of deformation coordination, the influence of process parameters on the titanium/stainless steel composite plate macro mechanical properties and microstructure changes was studied, and the relationship between microstructure evolution and macroscopic mechanical properties was established, to reveal the electro-plastic rolling titanium/stainless steel bonding mechanism. It provides theoretical and experimental basis for the preparation of high quality titanium/stainless steel composite plates, which has important scientific significance and practical application value.

钛/不锈钢复合板是耐腐蚀环境设备制造的理想选材，具有广阔的应用前景。但是由于钛、不锈钢机械性能差异比较大，轧制复合时极易出现变形不协调现象，当加热温度比较高时，复合界面易生成脆性金属间化合物，严重制约钛/不锈钢复合板的生产。本项目针对上述问题，提出了基于脉冲电流辅助钛/不锈钢轧制复合的工艺方法。通过有限元模拟和轧制复合实验研究电致塑性轧制过程中工艺参数对钛/不锈钢协调变形的影响规律，建立钛/不锈钢电致塑性轧制协调变形机制。在变形协调的基础上，研究工艺参数对钛/不锈钢复合板宏观力学性能和微观组织变化规律，并建立微观组织演变和宏观力学性能的联系，以此来揭示电致塑性轧制钛/不锈钢复合板的结合机理。为高品质钛/不锈钢复合板的制备提供理论和实验依据，具有重要的科学意义和实际的应用价值。

钛/不锈钢复合板很大限度地减少了对贵重金属钛的消耗，同时展现了出色的综合性能，因而广泛应用于海洋工程、航空航天等重要领域。本项目提出了脉冲电流辅助钛/不锈钢钢轧制复合的方法，利用脉冲电流的电致塑性效应在较低温度和较小压下率下实现钛/不锈钢复合板的制备。设计了合理稳定的电流施加装置和电流施加方式，探究了脉冲电流对钛/不锈钢复合板宏观力学性能和结合界面处的微观组织、微观结构、元素扩散、金属间化合物的成分及分布等的影响，揭示了钛/不锈钢电致塑性轧制复合机理。. 结果表明：（1）采用上下通电的方式能够保证复合板变形区内拥有较高且较均匀的电流密度。（2）在750℃下，19.5%时TC4/304复合板就能结合且获得较高的剪切强度，且结合强度并不随着压下率的增加而增加。而在58%压下量，随着温度升高，界面形成大量脆性化合物削弱了结合强度。（3）TA1/304复合板与TC4/304复合板存在相似的规律，24.4%压下率时复合板界面就能够实现结合，而54.4%压下率时界面FeTi和TiNi化合物以及由于Kirkendall效应产生孔洞导致结合强度急剧下降。（4）进一步在41.6%压下率下进行了不同电流密度的轧制实验，结果表明电流密度为1.15A/mm2时复合板剪切强度最大，达到356MPa。（5）针对750℃、41.6%压下量下制备的TA1/304复合板进行不同电流密度下的短时后处理。随着电流密度增加，化合物呈现增加趋势，28.91 A/mm2时化合物量过多严重削弱了复合板结合性能，脉冲电流能够在短时间内达到较好的效果。. 上述针对电塑性轧制钛/不锈钢复合板的相关研究方法和理论成果具有普适性，为电塑性轧制其他双金属复合板工艺设计提供了理论依据和实验方法。