Abstract: Rivet coating was a key factor influencing the formation and mechanics performances of riveted joints. The SSFR processes were used to join 6005A-T6 and 6A01-T5 aluminum alloy sheets herein. Three types of rivets including non-coated, Zn coated, and ZnNi coated were utilized to study the evolution laws of riveting force, energy input, and formation of the SSFR joints. Moreover, the remaining thickness of the coating layers at different positions in the joints and the diffusion of coating elements at the rivet/sheet interfaces was analyzed, and the influences of the rivet coating on the tensile-shear and cross-tension performances of the joints were investigated. The results indicate that the coating reduces the energy input generated by rivet rotation, thereby reducing the heat-affected zones of aluminum alloy materials. However, the decrease in energy input is not conducive to the formation of solid phase bonding between aluminum alloy materials in the rivet cavity, resulting in a decrease in the tensile-shear and cross-tension performances of the joints. Compared with Zn coating, the ZnNi coating has stronger wear resistance, and the remaining thickness still exceeds 40% after the stirring friction caused by high-speed rotation of rivets, which helps to improve the corrosion resistance of joints.

Key words: single-sided friction riveting(SSFR), joining without prefabricated hole, aluminum alloy, rivet coating, failure mechanism

摘要： 铆钉镀层是影响铆接接头成形及力学性能的重要因素，采用单边摩擦铆焊（SSFR）工艺连接6005A-T6和6A01-T5铝合金板材，研究了无镀层、Zn镀层、ZnNi镀层三种类型铆钉对应的SSFR接头成形过程铆接力、能量输入及接头宏微观成形的演化规律，分析了接头中不同位置的镀层剩余厚度及铆钉/板材界面的元素扩散，探究了铆钉镀层对接头拉剪和十字拉伸性能的影响。研究结果表明，镀层的引入降低了铆钉旋转产生的能量输入，从而使铝合金材料的热影响区减小，但能量输入的降低不利于铆钉空腔内铝合金材料间固相连接的形成，导致接头的拉剪和十字拉伸性能下降。与Zn镀层相比，ZnNi镀层的耐磨性较强，在铆钉高速旋转的搅拌摩擦作用下镀层剩余厚度仍超过40%，有助于提高接头的抗腐蚀性能。

关键词: 单边摩擦铆焊, 无预制孔连接, 铝合金, 铆钉镀层, 失效机理