铆钉对TA1与1420自冲铆接工艺及失效行为的影响

Influence of rivet on process and failure behavior of selfpiercing riveting in dissimilar sheets of TA1 and 1420 Al-Li alloys

采用自冲铆接技术对TA1与1420异质薄板组合铆接工艺进行了详细分析,且以长度6mm,硬度44HRC±2HRC和48HRC±2HRC的铆钉制备了TA1-1420接头(TAF)、1420-TA1接头(ATF)和TA1-1420接头(TAS).通过拉伸剪切和疲劳试验获取了三组接头的失效模式,借助电子扫描显微镜研究了铆钉对TA1与1420异质薄板接头失效行为的影响.结果表明,铆钉对TA1与1420异质薄板组合的铆接工艺有明显影响,采用6mm长度的铆钉能够实现对其有效连接,采用高硬度铆钉可减轻铆钉墩粗程度.铆钉硬度提高使接头失效部位由下板大变形区域下移至接头底部,导致异质薄板组合接头的失效行为存在差异.

Using self-piercing riveting (SPR),riveting processes of dissimilar sheet combinations in TA1 titanium and 1420 aluminum lithium alloy sheets were analyzed with different rivets in detail.And SPR joints of TA1-1420 (TAF),1420-TA1 (ATF) and TA1-1420 (TAS) were fabricated from different rivets with length of 6 mm and hardness of 44 HRC ± 2 HRC and 48 HRC ± 2 HRC,correspondingly.Through tensile-shear tests and fatigue tests,failure modes of three groups of joints were obtained.Furthermore,influences of rivet on failure behaviors of self-piercing riveting dissimilar sheets in TA1 and 1420 aluminum lithium alloys were analyzed using electron scanning microscope (SEM).Results show that: rivets have a significant influence on riveting processes of dissimilar sheet combinations.And they can be effectively connected with the rivets of proper length.The upsetting degree can be reduced with the hardness of rivets increased.As the hardness of rivets increased,the failure parts are changed from the huge deformation area to the bottom of the joint and the hardness of rivets also have a significant influence on the failure behaviors of these joints.