TC16钛合金螺栓及其连接30CrMnSiA钢板孔的疲劳行为

利用高频疲劳实验机和自制装置进行疲劳试验,研究了TC16钛合金螺栓连接30CrMnSiA高强度钢板结构的疲劳破坏行为,并通过扫描电镜(SEM)和有限元分析法分析了钢板和钛合金紧固件的失效机理。结果表明:30CrMnSiA高强度钢板件用TC16钛合金紧固件连接时在外加拉-拉疲劳载荷下,其疲劳破坏属于微动疲劳,寿命较带自由孔30CrMnSiA钢板件的常规疲劳寿命下降约60%,脱层和磨粒磨损是板孔微动疲劳的主要损伤形式。TC16钛合金紧固件连接30CrMnSiA高强度钢板结构在拉-拉疲劳载荷下,钛合金螺栓由于弯曲疲劳作用发生弯曲疲劳断裂,而非微动疲劳破坏。TC16钛合金螺栓表面进行阳极氧化处理有利于改善30CrMnSiA高强度钢连接板的微动疲劳性能。然而,钛合金螺栓表面进行阳极氧化处理由于韧性降低的缘故,却导致其常规弯曲疲劳抗力明显下降。

Fatigue Behavior of TC16 Titanium Alloy Bolts and 30CrMnSiA Steel Joint Holes

The fatigue failure behavior of TC16 titanium alloy bolts that connect 30CrMnSiA were investigated by using high frequencyfatigue experimental machines.The fatigue failuremechanisms of titanium alloy fasteners and steel plates were analyzedby using SEM and FEA.The results show that the connection of TC16 fasteners with 30CrMnSiA high-strength plates generates fretting fatigue(FF) under tensile-tensile load.The FF life of the plates is approximately 60% lower than the plain fatigue life of the plates with free holes.Delamination and abrasive wearare the main forms of FF damage of the plate holes.However the TC16 fasteners generate bending fatigue breakage instead of FF damage.The anodic oxidation surface treatment of TC16 bolts is good for improving the FF properties of 30CrMnSiA plates.On the other hand,the anodic oxidation of CT16 bolts greatly reducesplain bending fatigue resistance because of tenacity reduction.