摘要
研究了仿晶界型铁素体/粒状贝氏体复相钢轧态组织的韧性与裂纹扩展特点.与单一粒状贝氏体组织相比,仿晶界型铁素体/粒状贝氏体夏相组织具有更好的强韧性配合.适量仿晶界型铁素体的存在增加了复相组织的协调变形能力,提高了裂纹形成功;同时使裂纹扩展路径弯曲、分叉,微裂纹尖端钝化,在一定程度上提高了裂纹扩展功.在粒状贝氏体转变的第二阶段（富碳亚稳奥氏体→马氏体/奥氏体（M/A岛）缓冷,已转变的马氏体将进行自回火,并提高残余奥氏体的热稳定性,从而使复相组织的裂纹扩展功得到明显提高.
The as-rolled toughness and crack propagation behavior of grain boundary allotriomorphic ferrite/granular bainite duplex microstructure were studied. In comparison with single granular bainite, the duplex microstructure obtained under the condition of conventional rolling possesses good strength-toughness combination. The presence of grain boundary allotriomorphic ferrite can increase the compatible deformation capability of duplex microstructure, improve the crack initiation energy under impact loading; it leads to the formation of crack branching and curving propagation route, has some blunting effect on microcrack tip, and improves the crack propagation energy to a certain extent. Slow air-cooling at the second stage of granular bainite transformation (carbon-rich metastable austenite -->martensite-austenite constituent) has certain self-tempering effect on the as-transformed martensite, increases the thermal stability of retained austenite, and results in the improvement of crack propagation energy of this duplex microstructure.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2002年第3期255-260,共6页
Acta Metallurgica Sinica
