多轴复杂应力形式下TB6高强钛合金耳片的微动疲劳断裂研究  

Study on Fretting Fatigue Fracture of TB6 High Strength Titanium Alloy Lugs Under Multiaxial Complex Stress

作　　者：孔焕平 姜涛 刘昌奎 应少军 赵凯 KONG Huanping;JIANG Tao;LIU Changkui;YING Shaojun;ZHAO Kai(AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;Beijing Key Laboratory of Aeronautical Materials Testing and Evaluation,Beijing 100095,China;Key Laboratory of Science and Technology on Aeronautical Materials Testing and Evaluation of Aero Engine Corporation of China,Beijing 100095,China;Aviation Key Laboratory of Science and Technology on Materials Testing and Evaluation,Beijing 100095,China;AVIC Changhe Aircraft Industry(Group)Corporation Ltd.,Jingdezhen 333000,China)

机构地区：[1]中国航发北京航空材料研究院,北京100095 [2]航空材料检测与评价北京市重点实验室,北京100095 [3]中国航空发动机集团材料检测与评价重点实验室,北京100095 [4]材料检测与评价航空科技重点实验室,北京100095 [5]中国航空工业昌河飞机(集团)有限公司,景德镇333000

出　　处：《材料导报》2020年第14期14134-14139,共6页Materials Reports

基　　金：航空科学基金项目(2016ZF21005).

摘　　要：本实验研究了TB6高强钛合金在拉-扭多轴应力条件下的微动疲劳断裂机理,并结合宏微观观察、残余应力测试、计算机模拟分析了不同工艺条件的耳片在拉-扭疲劳试验应力下的微动疲劳寿命差异,研究了微动疲劳裂纹的萌生及扩展特性,揭示了耳片裂纹萌生机制。结果表明:二次挤压耳片的断口扩展区面积比例较大,说明其拉-扭疲劳扩展更为充分。经二次挤压后,耳片的拉-扭微动疲劳总寿命得到延长,且裂纹萌生寿命均占总寿命的95%以上;二次挤压后耳片的裂纹萌生驱动力较低,呈现较高的裂纹萌生抗力。各断口均起源于耳片内孔微动磨损印迹较重处,大面积连续片状的微动磨损印迹表明二次挤压后的钛合金微动疲劳敏感性大大降低。经挤压强化后,孔壁形成了较高幅值的残余压应力层和组织强化层,可以有效地抑制裂纹的萌生和扩展。耳片内孔微动磨损层的形成是机械诱导机制和热诱导机制共同作用的结果,其最终磨损形式为疲劳磨损。The fretting fatigue fracture mechanism of TB6 high strength titanium alloy under tension-torsion multiaxial stress was studied.Based on macro and micro observation,residual stress testing and computer simulation,the difference of the fretting fatigue life of the lugs with different treated conditions under tension-torsion fatigue test stress was analyzed.The characteristics of fretting fatigue crack initiation and propagation under tension-torsion fatigue test were studied,and the mechanism of fretting crack initiation was revealed.The results show that fractures propagation area of twice extrusion lugs is larger.After twice extrusion,the total life of fretting fatigue of lugs is greatly extended,and the crack initiation life accounts for more than 95%of the total life.The driving force of the crack initiation is lower and the resistance against crack initiation is better.Each fracture originates from the marks on the inner hole of lugs have heavier fretting wear.After extrusion strengthening,a higher residual compressive stress layer and a tissue strengthening layer are formed on the hole wall,which can effectively inhibit the initiation and propagation of the cracks.The formation of fretting wear layer in the inner hole of lugs is the result of the combined action of mechanical mechanism and thermal induction mechanism,and the final wear form of lugs is fatigue wear.

关 键 词：多轴复杂应力 微动疲劳 裂纹萌生抗力 微动磨损 疲劳磨损 

分 类 号：TG115[金属学及工艺—物理冶金]