累积叠轧Al/Cu复合板界面反应层核-壳结构形成机制

采用累积叠轧(ARB)结合多次退火处理制备了Al/Cu复合板,重点研究了Al/Cu界面反应层核-壳结构形成机制. 结果表明:Al/Cu界面反应层的形成主要依赖于退火过程中铜原子在界面处的扩散,反应产物包括Al₂Cu、AlCu、Al₄Cu₉. 轧制变形致使反应层破碎并在基体中均匀分布,轧后退火处理导致新的反应层不断形成.最终经多次叠轧及退火处理,原始铜板材全部转变为椭球状具有核-壳结构的Al/Cu金属间化合物颗粒. 8道次复合板抗拉强度最高,达到176.8 MPa,是退火态1060抗拉强度的1.74倍;0道次复合板延伸率较好,主要是Al/Cu界面分层后铝层均匀塑性变形,应力缓慢释放所致.

Formation mechanism of core-shell structure in interface reaction layer of accumulative pack-rolled Al/Cu composite sheet

The Al/Cu composite sheet was fabricated by means of accumulative pack-roll (ARB) incorporated with multiple annealing treatment and the core-shell structure formation mechanism of Al/Cu interfacial reaction layer was emphatically investigated. The result showed that atomic diffusion of copper at Al/Cu interface during annealing would play a key role in the formation of Al/Cu interfacial reaction layer and the resultants would include intermetallic compounds Al₂Cu, AlCu and Al₄Cu₉. The rolling deformation would make the reaction layer broken and distributed uniformly the matrix. The annealing treatment after rolling would lead to continuous formation of new interface reaction layer. Finally, after multiple pack-rolled pass and annealing treatment, the entire primary copper sheets would be transformed into axiolitic Al/Cu intermetallic compound particles with core-shell structure. The composite sheet after eight ARB passes would have highest ultimate tensile strength (UTS) of 176.8 MPa which would be 1.74 times of that of annealed 1060. The elongation of composite sheet without rolling would be better; this was basically due to that the aluminium layer would deform plastically and uniformly after Al/Cu interface delamination and the stress would slowly be released.