Q235碳素钢超细铁素体在奥氏体内的形核

Nucleation of Ultra-fine Ferrite in Austenite of A Q235 Low Carbon Steel

  • 摘要: 利用扫描电镜观察了Q235碳素钢形变强化相变过程中超细铁素体在奥氏体内部的形核;使用背散射电子衍射(EBSD)技术分析了析出的铁素体取向.结果表明,随内、外界条件不同,奥氏体内有两类典型的铁素体形核地点:形变带及奥氏体晶界附近的形变不均匀区原始奥氏体晶粒尺寸的增加,形变温度的降低有利于铁素体的形变带形核.在A3-Ar3的超细铁素体最佳形成温度区间,靠近A3形变可使铁素体及第2组织均匀分布.形变带形核造成带状分布的铁素体及第2相,不仅形貌上出现方向性,铁素体取向也出现择优.

     

    Abstract: The nucleation of ultra-fine ferrite inside austenite was followed during deformation-enhanced transformation in a Q235 low carbon steel. EBSD technique was applied to reveal the orientation features of ferrite formed at different places. Results indicate that there are two typical nucleation sites inside austenite, namely, deformation bands and deformation inhomogeneities near austenite grain boundaries. Increasing austenite grain size and decreasing deformation temperature favor to the ferrite formation at deformation bands. In the suitable deformation temperatures of A3-Ar3 for ultra-fine ferrite, the deformation near A, leads to a uniform distribution of ferrite as well as second phases. The band-like ferrite and second phases caused by the nucleation at deformation bands gives rise to not only the anisotropy in microstructure but also in ferrite orientation.

     

/

返回文章
返回