2A10铝合金铆钉电磁铆接镦头变形过程研究

Research on deformation process of 2A10 aluminum alloy rivet head in electromagnetic riveting

采用试验方法,通过控制冲头下压量,得到离散化的2A10铝合金铆钉试样,研究铆钉镦头微观组织的演化以及绝热剪切带的萌生和扩展过程。结果表明,铆钉镦头不同区域变形差异大,中心区和对角线区域起始变形严重,剪切带最先在中心区和对角线区域萌生,但主、次剪切带萌生并不同步,主剪切带出现较早,逐渐扩展形成类抛物线形态,次剪切带出现后逐渐消失,转而在侧面变形区出现一些分散的剪切带。随着下压量加大,主剪切带愈发清晰,宽度增加,带内晶粒破碎严重,沿剪切带方向被拉长,晶界模糊;下压量达到82.12%时,主剪切带最为明显,但铆钉镦头并未出现裂纹。

Using the experimental method,the discretized 2 A10 aluminum alloy rivet specimens were obtained by controlling the depression amount of the punch,and the microstructure evolution of rivet head as well as the initiation and expansion processes of the adiabatic shear band were studied.The results show that the difference of deformation in different areas of the rivet head is large,the initial deformation of the central area and the diagonal area is serious,and the shear band is firstly initiated in the central area and the diagonal area,but the initiation of primary and secondary shear bands are not synchronized.The main shear band appears earlier and gradually expands to a parabolic morphology.The secondary shear band disappears gradually,and some scattered shear bands appear in the lateral deformation area.As the depression amount increases,the main shear band becomes clearer,the width increases,the in-band grains break seriously which are elongated along the direction of the shear band with blurry grain boundary.The main shear band is the most obvious when the depression amount reaches to 82.12%,while the cracks do not appear in rivet head.