低碳钢形变强化相变时铁素体织构类型的分析

利用背散射电子衍射取向成像技术分析了在热模拟单向压缩条件下Q235碳素钢形变强化相变时铁素体织构的类型。结果表明,在利用形变强化相变实现铁素体的超细化过程中会出现铁素体的相交织构和形变织构,在大应变条件下还会出现动态再结晶织构。在形变强化相变后细晶铁素体在整体上表现为以〈111〉方向为主的线织构。主要的相交织构在粗晶奥氏体内部形变带形核时产生并与〈111〉织构对应。形变织构是在形变时形成的铁素体受到继续变形所致,在形变强化相变过程中及完成后都会产生,对应〈111〉及〈100〉方向的线织构,随着形变的加大,〈100〉方向的织构增加得更快,形变温度的降低有利于形变织构的加强。在形变量很大且形变温度比较合适时(但不能过低)会发生铁素体的动态再结晶,它以连续的方式进行,导致形变织构的进一步加强,并使晶粒均匀细化。

Analysis of textural features during ferrite refinement by deformation-enhanced transformation in a low carbon steel

The textural features during ferrite refinement by deformation enhanced transformation were analyzed by means of orientation mapping based on the EBSD technique in a Q235 low carbon steel. Results show that transformation texture, deformation texture and/or dynamic recrystallization texture can occur in this process. In general the <111> fiber texture is dominant which is in contrast to the pronounced <100> texture related with the heavy strain on ferrite below A1. Transformation texture was evolved mainly at the deformation bands inside coarse austenite grains and is related to the <111> component. Deformation texture, due to the constant loading of strains on ferrite, was developed both during deformation enhanced transformation and thereafter. It is related to the <111> as well as the <100> component. As strain increased the<100> component was enhanced faster and the lower temperature favored deformation textures. At heavy strain and suitable temperatures, dynamic recrystallization proceeded in a continuous way leading to an enhanced deformation texture and further refinement of ferrite.