Acta Metallurgica Sinica (English Letters) ›› 1991, Vol. 4 ›› Issue (2): 123-128.

• Research paper • Previous Articles     Next Articles

MECHANISM MAP OF TORSIONAL FATIGUE FRACTURE

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   

  • Received:1991-04-25 Revised:1991-04-25 Online:1991-04-25 Published:2009-10-10

Abstract: 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.

Key words: mechanism map, torsional fatigue, fracture