工程科学学报，第40卷，第4期：478-484,2018年4月 Chinese Journal of Engineering,Vol.40,No.4:478-484,April 2018 DOI:10.13374/j.issn2095-9389.2018.04.011:http://journals.ustb.edu.cn 钛铝异质自冲铆接头疲劳性能及失效机理 刘洋，何晓聪，张先炼 昆明理工大学机电工程学院，昆明650500 ☒通倍作者，E-mail:xiaocong_hc@126.com 摘要对纯钛(TA1)和铝锂合金(AL1420)异质单搭自冲铆接头进行静力学实验和疲劳实验研究，通过三参数经验公式采 用S一V曲线拟合法绘制接头的S一V曲线，分析接头的疲劳性能：采用扫描电子显微镜对接头疲劳断口进行观测，研究接头的 微观疲劳失效机理.结果表明：接头的静力学性能与疲劳性能不具有一致性，TA1一AL1420(TA)接头静力学性能更优，但其疲 劳性能比AL1420-TA1(AT)接头差：TA接头疲劳失效形式为下板断裂，疲劳裂纹萌生于靠近铆钉脚处的板材区域，随后沿着 板宽方向扩展，最终导致下板完全断裂.AT接头在短寿命区因铆钉断裂失效，铆钉的断口属于脆性疲劳断裂：在中长寿命区 出现铆钉新裂和下板断裂的混合失效形式，疲劳裂纹从下板一端萌生，沿着板宽向另一端方向扩展，导致下板断裂失效 关键词自冲铆：AL1420铝锂合金：TA1纯钛：疲劳特性：扫描电子显微镜 分类号TG405 Fatigue properties and failure mechanisms of self-piercing riveted joints in titanium and aluminum alloy dissimilar sheets LIU Yang,HE Xiao-cong,ZHANG Xian-ian Faculty of Mechanical and Electrical Engineering,Kunming University of Science and Technology,Kunming 650500,China Corresponding author,E-mail:xiaocong_he@126.com ABSTRACT A static test and fatigue test of dissimilar single-lap self-piercing riveted joints were conducted for pure titanium (TAl) and aluminum-lithium alloy (ALl420).The fatigue performance of the joints was analyzed on the basis of the S-N curves:specifical- ly,a fitting method was used to construct the S-N curves of the joints using three empirical parameters.Scanning electron microscopy was used to study the fatigue fracture surfaces of the joints and the microfatigue failure mechanism of the joints.The results indicate that the static performance and fatigue characteristics of the joints are inconsistent:the TAl-AL1420(TA)joint exhibits better static performance,whereas its fatigue characteristics are worse than those of the ALl420-TAl (AT)joint.The fatigue failure mode of the TA joint for the lower sheet is fracture:the fatigue crack appears in the sheet area around the rivet tail and extends along the width of the sheet,leading to complete fracture of the lower sheet.The loss of efficacy of the AT joint in the short-ife region is related to frac- ture failure of the rivet,which exhibits brittle fatigue fracture.A mixed failure mode of rivet fracture and lower sheet fracture occurs in the middle-ong life region,and a fatigue crack appears from one side of the lower sheet,extends along the width of the sheet to the other direction,and eventually lead to the failure of the lower sheet. KEY WORDS self-piercing riveting:AL1420 aluminum-ithium alloys:TAl pure titanium:fatigue property:scanning electron mi- croscopy 随着环境污染和全球能源危机问题日益严重，车身轻量化对汽车节能减排具有重要意义，也顺应 收稿日期：2017-0605 基金项目：国家自然科学基金资助项目(51565023)工程科学学报，第 40 卷，第 4 期: 478--484，2018 年 4 月 Chinese Journal of Engineering，Vol． 40，No． 4: 478--484，April 2018 DOI: 10． 13374 /j． issn2095--9389． 2018． 04． 011; http: / /journals． ustb． edu． cn 钛铝异质自冲铆接头疲劳性能及失效机理 刘 洋，何晓聪，张先炼 昆明理工大学机电工程学院，昆明 650500 通信作者，E-mail: xiaocong_he@ 126． com 摘 要 对纯钛( TA1) 和铝锂合金( AL1420) 异质单搭自冲铆接头进行静力学实验和疲劳实验研究，通过三参数经验公式采 用 S--N 曲线拟合法绘制接头的 S--N 曲线，分析接头的疲劳性能; 采用扫描电子显微镜对接头疲劳断口进行观测，研究接头的 微观疲劳失效机理． 结果表明: 接头的静力学性能与疲劳性能不具有一致性，TA1--AL1420( TA) 接头静力学性能更优，但其疲 劳性能比 AL1420--TA1( AT) 接头差; TA 接头疲劳失效形式为下板断裂，疲劳裂纹萌生于靠近铆钉脚处的板材区域，随后沿着 板宽方向扩展，最终导致下板完全断裂． AT 接头在短寿命区因铆钉断裂失效，铆钉的断口属于脆性疲劳断裂; 在中长寿命区 出现铆钉断裂和下板断裂的混合失效形式，疲劳裂纹从下板一端萌生，沿着板宽向另一端方向扩展，导致下板断裂失效． 关键词 自冲铆; AL1420 铝锂合金; TA1 纯钛; 疲劳特性; 扫描电子显微镜 分类号 TG405 收稿日期: 2017--06--05 基金项目: 国家自然科学基金资助项目( 51565023) Fatigue properties and failure mechanisms of self-piercing riveted joints in titanium and aluminum alloy dissimilar sheets LIU Yang，HE Xiao-cong ，ZHANG Xian-lian Faculty of Mechanical and Electrical Engineering，Kunming University of Science and Technology，Kunming 650500，China Corresponding author，E-mail: xiaocong_he@ 126． com ABSTＲACT A static test and fatigue test of dissimilar single-lap self-piercing riveted joints were conducted for pure titanium ( TA1) and aluminum--lithium alloy ( AL1420) ． The fatigue performance of the joints was analyzed on the basis of the S--N curves; specifical￾ly，a fitting method was used to construct the S--N curves of the joints using three empirical parameters． Scanning electron microscopy was used to study the fatigue fracture surfaces of the joints and the microfatigue failure mechanism of the joints． The results indicate that the static performance and fatigue characteristics of the joints are inconsistent: the TA1--AL1420( TA) joint exhibits better static performance，whereas its fatigue characteristics are worse than those of the AL1420--TA1( AT) joint． The fatigue failure mode of the TA joint for the lower sheet is fracture; the fatigue crack appears in the sheet area around the rivet tail and extends along the width of the sheet，leading to complete fracture of the lower sheet． The loss of efficacy of the AT joint in the short-life region is related to frac￾ture failure of the rivet，which exhibits brittle fatigue fracture． A mixed failure mode of rivet fracture and lower sheet fracture occurs in the middle-long life region，and a fatigue crack appears from one side of the lower sheet，extends along the width of the sheet to the other direction，and eventually lead to the failure of the lower sheet． KEY WOＲDS self-piercing riveting; AL1420 aluminum-lithium alloys; TA1 pure titanium; fatigue property; scanning electron mi￾croscopy 随着环境污染和全球能源危机问题日益严重， 车身轻量化对汽车节能减排具有重要意义，也顺应