冷轧和退火对压延铜箔残余应力和力学性能的影响

Influence of Cold Rolling and Annealing on Residual Stress and Mechanical Properties of Rolled Copper Foil

对150μm厚铜箔母材进行4道次可逆冷轧,轧制至35μm厚,再在180℃下进行1 h退火处理,研究了冷轧和退火对压延铜箔显微组织、表面残余应力以及力学性能的影响。结果表明:经过冷轧处理后,铜箔的晶粒明显细化,平均晶粒尺寸减小至5.7μm,织构由退火织构转变为形变织构;经退火处理后,平均晶粒尺寸增大至9.4μm,织构恢复为退火织构。冷轧后铜箔的表面残余应力急剧增加至543.02 MPa,硬度增加,平均耐弯折疲劳寿命延长,平行于轧制方向(RD)的抗拉强度提高,而断后伸长率和TD面(TD为轧板横向)的表面粗糙度下降。经退火处理后,铜箔的表面残余应力恢复至237.47 MPa,硬度降低,TD面的表面粗糙度稍微增加,抗拉强度降低和断后伸长率有所提高,平均耐弯折疲劳寿命进一步延长。

A 150μm-thick copper foil base metal was rolled by reversible cold rolling for four passes.The rolled copper foil with thickness of 35μm was obtained,and was annealed at 180°C for 1 h.The effects of cold rolling and annealing on the microstructure,surface residual stress,and mechanical properties of the rolled copper foil was studied.The results show that after cold rolling,the grain size of the copper foil was significantly refined,the average grain size was reduced to 5.7μm,and the texture changed from annealing texture to deformation texture.After annealing,the average grain size increased to 9.4μm and the texture was reverted to the annealing texture.After cold rolling,the surface residual stress of the copper foil increased sharply to 543.02 MPa,the hardness increased,the average flexural fatigue life was extended,the tensile strength along rolling direction(RD)was improved,and the elongation after fracture and the surface roughness of TD(transverse direction)face decreased.After annealing,the surface residual stress of the copper foil was recovered to 237.47 MPa,the hardness was reduced,the TD surface roughness slightly increased,the tensile strength decreased and elongation after fracture were slighthy improved,and the average flexural fatigue life was further extended.