电磁场对水平双辊铸轧Ti/Al/Cu复合板界面结合强度的影响

Effects of electromagnetic fields on interfacial bonding strength of Ti/Al/Cu clad sheet processed by horizontal twin-roll casting

利用水平双辊铸轧技术制备Ti/Al/Cu复合板,通过在铸轧过程中施加脉冲电场和电磁振荡场,研究不同外场对铸轧复合板界面结合强度的影响。结果表明:电磁场对铸轧过程的稳定性没有影响。施加脉冲电场和电磁振荡场后,Ti/Al界面和Cu/Al界面的扩散层厚度增加,界面结合强度显著提高。施加电磁振荡场后,在铸轧区的液穴内产生交变的电磁体积力。在电磁体积力的作用下,铝熔体内部产生震荡效应并对金属带表面进行冲刷,使金属带表面新形成的晶核脱离。此外,震荡效应使得金属带与铝熔体接触处的温度梯度降低,凝固速度减慢从而延长固-液接触时间。这些作用使得熔体在金属带表面铺展湿润更加充分,促进了原子间的互扩散,从而产生了更多的冶金结合区域并增大了冶金结合的强度。

A Ti/Al/Cu clad sheet was fabricated by using horizontal twin-roll casting(HTRC)with the application of pulsed electric field(PEF)and electromagnetic oscillation field(EOF),and the effects of different external fields on interfacial bonding strength were studied.The results show that the external electromagnetic fields have little influence on the stability of HTRC process.With the application of PEF and EOF,the width of diffusion layer at the Ti/Al and Cu/Al interface increases obviously.The interface bonding strength is significantly improved.When the EOF is applied,the electromagnetic volumetric force is generated in the liquid cavity of cast-rolling zone.Under the action of the electromagnetic volume force,aluminum melt oscillates repeatedly,which scours the surface of the strips and makes the newly formed crystal nuclei fall off the surface of strips.In addition,the oscillation effect reduces the temperature gradient at the contact area between strip and melt and slows down the solidification process,thus prolonging the contact time between aluminum and strips.All of these effects make the melt spread more sufficient on the surface of strips and promote the interdi-ffusion between atoms.As a result,more metallurgical bonding regions are formed and enhanced.