【摘要】 采用金相显微镜（MM）、扫描电镜（SEM）、透射电镜（TEM）、万能拉伸试验机等对高强度钢筋的显微组织、第二相、断口和力学性能进行表征和试验.结果表明：3种试验钢筋的显微组织均为铁素体+珠光体，其中3~#试验钢筋中还含有少量贝氏体；3#试验钢筋中主要析出物为铌钒复合碳氮化物（（Nb,V）(C,N)），呈圆形状，平均粒径为10 nm，在铁素体晶界和珠光体片层间析出；3种试验钢筋的拉伸断口均为韧性断裂，断口上分布着等轴韧窝；随着Nb含量的增加，试验钢筋的抗拉强度和屈服强度增加，但其断后伸长率有所降低；3~#试验钢筋的抗拉强度和屈服强度最大，分别为795、525 MPa，断后伸长率较1~#和2~#试验钢筋小，为21.6%.更多还原

【Abstract】 The microstructure,second phase,fracture morphology,mechanical properties of high-strength rebars were characterized by metallographic microscope(MM),scanning electron microscope(SEM),transmission electron microscopy(TEM) and universal tensile testing machine. The results show that the microstructure of 1~#-3~# experimental steel rebars are ferrite + pearlite,and the 3~# experimental steel rebar contains a small amount of bainite;the main precipitate of 3~# rebar experimental steel is niobium vanadium composite carbonitride((Nb,V)(C,N)),which is round in shape and precipitate on ferrite grain boundary and pearlite lamellar,with the average particle size of 10 nm;the tensile fracture of 1~#-3~# experimental steel rebars belong to ductile fracture,and the equiaxed dimples are distributed on the fracture;with the increase of Nb content,the tensile strength and yield strength of experimental steel rebar increase,the elongation after fracture decrease;the tensile strength and yield strength of 3~# experimental steel rebar is the largest,reach 795,525 MPa,respectively,the elongation after fracture is 21.6%.更多还原