摘要
采用空气炮发射钨钢球弹体以不同角度撞击S38C车轴钢试样表面预制弹坑缺陷;利用四点弯曲疲劳试验法获得缺陷试样的疲劳强度;使用超景深光学显微镜表征弹坑的几何形态和截面组织;借助扫描电子显微镜观察弹坑和疲劳断口形貌。结果表明:在200 m/s冲击下,30°冲击对缺陷试样疲劳强度的影响较小,其余角度(45°、60°、75°和90°)冲击试样的疲劳强度随着冲击角度的增大而下降,其中90°冲击试样的疲劳强度较光滑试样下降约40%。弹坑底部会形成绝热剪切带(ASBs)以及由剪切带开裂形成的裂纹,倾斜冲击试样疲劳裂纹源主要位于弹坑出射区边缘材料失效处,垂直冲击试样疲劳裂纹从弹坑两侧扩展。损伤试样的疲劳强度随缺陷深度d和缺陷截面积平方根的增大有相似的下降趋势。
In order to produce crater defects,compressed-gas gun was used to shoot tungsten steel projectiles at different angles onto the surface of S38C axle steel specimens.The fatigue strength of the defective specimens were obtained by the four-point bending fatigue test method.The geometry parameter and cross-section structure of craters were characterized by optical microscope,and the crater morphology and fractography after fatigue test were detected by scanning electron microscope.The results show that under the 200 m/s shooting speed,the 30°impact has little effect on the fatigue strength of the defective specimens,and the fatigue strength of damaged specimens decreased with the increasement of incident angle(45°,60°,75°and 90°).Compared with smooth specimens,the fatigue strength of 90°impact specimens were declined about 40%.The adiabatic shear bands(ASBs)and even cracks were informed below the damaged craters.The fatigue crack mainly nucleated from rim area of crater for the glanced impacted specimens,while fatigue crack started from both sides of impact crater for the perpendicularly impacted one.The fatigue strength of damaged specimens decreased with the increasement of defective depth and cross-section √area.
作者
余明华
高杰维
刘里根
李亚波
韩靖
戴光泽
赵君文
YU Minghua;GAO Jiewei;LIU Ligen;LI Yabo;HAN Jing;DAI Guangze;ZHAO Junwen(School of Materials Science and Engineering,Southwest Jiaotong University,Chengdu 610031,China;State Key Laboratory of Traction Power,Southwest Jiaotong University,Chengdu 610031,China;School of Mechanical and Electrical Engineering,University of Electronic Science and Technology of China,Chengdu 611731,China;CRRC Qingdao Sifang Co.,Ltd.,Qingdao 266111,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2021年第20期20092-20098,共7页
Materials Reports
基金
牵引动力国家重点实验室自主课题(2019TPL-T21)
国家重点研发计划(2018YFB1201704-03)。
关键词
外物损伤
疲劳强度
S38C车轴钢
绝热剪切带
foreign object damage
fatigue strength
S38C axle steel
adiabatic shear bands
