20CrMnTi钢的位错密度及晶体结构

Determination of dislocation densities and crystal structure on 20CrMnTi steel

采用X射线衍射法及新的线性分析理论,准确地测量了不同应变量时20CrMnTi钢的位错密度,分析了应变量与位错密度的关系。结果表明:位错密度随变形量的增加而提高,退火状态时位错密度较低。透射电镜试验证明了20CrMnTi退火后的组织为铁素体和珠光体,晶内位错表态为"曲折"形的位错线,变形后形成胞状结构,同时有孪晶出现。胞状结构的出现大大提高了钢的强度。

Dislocation densities in 20CrMnTi steel under different sizes of strain were determined exactly by X-ray diffraction method and a new profile analysis theory. The relation of strain and dislocation densities was analyzed. The results show that the increase of dislocation density is accompanied by the increase of deformation amount. The dislocation density has lower value when the steel is annealed. TEM tests prove that 20CrMnTi become ferrite and pearlite after annealing. Intragranular dislocation appears as zigzag dislocation line and comes into being cell structure with the appearance of twin crystals after deformation. Cell structure improves the strength of steel greatly.