摘要
对锻造TC4钛合金电子束焊接(EBW)接头进行了应力控制的高周疲劳试验和应变控制的低周疲劳试验,利用扫描电子显微镜对疲劳断口进行观察与分析,研究了疲劳裂纹的起裂机制.研究结果表明:所有的高周疲劳试样裂纹起裂位置和最后断裂位置均发生在母材区,而低周疲劳试验试样断裂位置表现出不确定性,在焊缝区和母材区均可导致裂纹起裂.高周疲劳载荷下,裂纹起源于表面滑移;低周疲劳时,裂纹可能在接头母材区的表面起裂,也可能在接头焊缝的内部缺陷处起裂,裂纹起裂模式取决于载荷大小.
Stress controlled high-cycle fatigue（HCF） test and strain controlled low-cycle fatigue（LCF） test for electron beam welding（EBW） joints of forged TC4 alloy were investigated at room temperature.Fracture surfaces were observed by scanning electron microscope（SEM）,and the crack initiation mechanism of fatigue failure was analyzed.The results show that all HCF specimens are fractured in the base material（BM） observed by SEM,while LCF specimens are mainly ruptured at fusion zone（FZ） and BM.Due to low stress level in HCF test,the crack of joints is initiated near the surface,while the crack of the joint in LCF test is initiated not only near the surface but also in the interior defects.The crack initiation mode depends on the load.
出处
《航空动力学报》
EI
CAS
CSCD
北大核心
2013年第2期264-269,共6页
Journal of Aerospace Power
