胡志忠
,
吴玉声
,
蔡和平
,
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
,
torsional fatigue
,
fracture
郭洪强
机械工程材料
用扭转疲劳试验机对63Sn-37Pb和Sn-3Ag-0.5Cu两种合金钎料在扭转载荷下的低周疲劳性能进行了研究.结果表明:两种钎料均为循环软化材料,它们的变形主要由塑性变形决定;两种钎料的疲劳寿命均随着剪应变幅的减小而显著增大;在相同的剪应变幅下,Sn-3Ag-0.5Cu合金钎料的疲劳寿命比63Sn-37Pb钎料的长,即Sn-3Ag-0.5Cu合金钎料的抗剪切疲劳能力更强.
关键词:
63Sn-37Pb合金
,
Sn-3Ag-0.5Cu合金
,
低周疲劳
,
扭转疲劳
,
疲劳寿命
HU Zhizhong WU Yusheng CAI Heping MA Lihua Xi′an jiaotong University
,
Xi′an
,
China Senior Engineer
,
Res.Inst.for Strength of Metals
,
Xi′an jiaotong University
,
Xi′an 710049
,
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
,
null
,
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