HU Zhizhong WU Yusheng CAI Heping MA Lihua Xi′an jiaotong University
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Xi′an
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China Senior Engineer
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Res.Inst.for Strength of Metals
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Xi′an jiaotong University
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Xi′an 710049
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China
金属学报(英文版)
Studies have been made of the torsional fatigue fracture life of notched specimens,the macroscopic fractography and microscopic fracture mechanism of steel 40Cr after various tempering treatments under different stresses,With the increase of stress,the fracture model changes from normal stress fracture to longitudinal shear one,and then transversal shear one. Under same stress,with the increase of strength,the fracture mode transfers from shear to normal stress fracture.The mechanism of normal stress fracture may be:transgranular frac- ture→striation+intergranular fracture→dimple+intergranular fracture,and of shear fracture may be:transgranular fracture→shear trace→dimple.Based on the experimental results,a fracture mechanism map of torsional fatigue has been drawn up.
关键词:
mechanism map
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null
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胡志忠
,
吴玉声
,
蔡和平
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马丽华
金属学报
本文研究了40Cr钢不同回火态,不同应力水平下缺口扭转疲劳断裂的寿命、宏观断口类型和微观断裂机制。断口分析表明,在同一回火温度下,随着应力的升高,断裂类型由正应力断裂→纵向剪切断裂→横向剪切断裂转变;同一应力水平下,随着强度的增加,断裂类型由剪切型向正断型转变;正断型的断裂机制为:T→S+I→D+I,剪切型的断裂机制为:T→S′→D。根据本工作结果总结出扭转疲劳断裂机制图。
关键词:
扭转疲劳
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torsional fatigue
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fracture
