摘要
The fracture characteristics of fully pearlitic steel wires with fine and randomly oriented lamellae have been investigated after tension and torsion, respectively. It is found that the predominant fracture mode under small pre- deformation is dimple. The analysis of the colony size and the lamellar structure near the fracture surface indicates that each dimple roots from one colony. A simulation of tensile deformation with several pearlitic colonies based on the real scanning electron microscopy （SEM） observation shows that the plastic deformation concentrates and the stress t^hxialit~＂ is larger ~it the boundaries bf colonies. It demonstrates the microe/＇a^ks initialize at colony boundaries. Thus, the colony size is a significant factor for fracture behaviors under small pre-deformation. On the other hand, the fracture surface is investigated after large pre-deformation via torsion. The results show that fracture characteristics vary with radius from dimples, elongated dimples to the fibrous structure. It indicates that the fracture charac-teristics are dependent on the pre-deformation. The fracture mode under large pre-deformation becomes an anisotropic fibrous structure instead of dimples.
The fracture characteristics of fully pearlitic steel wires with fine and randomly oriented lamellae have been investigated after tension and torsion, respectively. It is found that the predominant fracture mode under small pre- deformation is dimple. The analysis of the colony size and the lamellar structure near the fracture surface indicates that each dimple roots from one colony. A simulation of tensile deformation with several pearlitic colonies based on the real scanning electron microscopy （SEM） observation shows that the plastic deformation concentrates and the stress t^hxialit~＂ is larger ~it the boundaries bf colonies. It demonstrates the microe/＇a^ks initialize at colony boundaries. Thus, the colony size is a significant factor for fracture behaviors under small pre-deformation. On the other hand, the fracture surface is investigated after large pre-deformation via torsion. The results show that fracture characteristics vary with radius from dimples, elongated dimples to the fibrous structure. It indicates that the fracture charac-teristics are dependent on the pre-deformation. The fracture mode under large pre-deformation becomes an anisotropic fibrous structure instead of dimples.
基金
Item Sponsored by National Natural Science Foundation of China(51034009,51404158)
Doctoral Initiation Foundation of Liaoning Province of China(201601176)
