摘要
对含铁素体和球光体或马氏体的双相钢形变过程中的声发射(AE)研究表明:屈服区的 AE 总是在宏观范性形变开始处达到峰值,随后下降,L(u|¨)ders 带传播过程中的 AE 与 L(u|¨)ders 应变εL 相关,且单位εL 上发射的 AE 能量随εL 增加而减小;从双相区淬火,在大于某一临界值的冷却速度区间,除屈服区有—AE 峰外,屈服后出现第二个声发射峰。
The acoustic emission(AE) study during deformation of dualphase steels consisting of ferrite(F) and pearlite(P)/martensite(M) indicates thatthe AE peak in the yielding region always appears at the beginning of themacroplastic deformation.After macroyielding started the AE decreases becausethe dislocation velocity decreases.The total AE energy (?)_(LP) emitted duringL(?)ders band propagation is related to the L(?)ders strain ε_L and (?)_(LP)/ε_L decre-ases as ε_L increases because of the increasing in ε_L resulting from the decrea-sing in dislocation velocity;After quenching from the two-phase region atcooling rates larger than a certain critical value,a second AE peak,whichis produced by the cracking mainly at the interfaces between M and F andsecondly in mertensitic particles,appears in a certain plastic strain range in ad-dition to the one in the yielding region.As the cooling rate becomes too fast,the AE peak in the yielding region disappears and the second AE peak can notcomplete due to the brittle fracture.
关键词
双相钢
声发射
位错速度
Lüders带
裂纹成核
dual-phase steel
acoustic emission
dislocation velocity
Lüders band
crack nucleation
