Zaefferer S, Romano P, Friedel F
Max Planck Institute for Iron Research, D-40237 Dusseldorf, Germany.
J Microsc. 2008 Jun;230(Pt 3):499-508. doi: 10.1111/j.1365-2818.2008.02010.x.
Bainite is thought to play an important role for the chemical and mechanical stabilization of metastable austenite in low-alloyed TRIP steels. Therefore, in order to understand and improve the material properties, it is important to locate and quantify the bainitic phase. To this aim, electron backscatter diffraction-based orientation microscopy has been employed. The main difficulty herewith is to distinguish bainitic ferrite from ferrite because both have bcc crystal structure. The most important difference between them is the occurrence of transformation induced geometrically necessary dislocations in the bainitic phase. To determine the areas with larger geometrically necessary dislocation density, the following orientation microscopy maps were explored: pattern quality maps, grain reference orientation deviation maps and kernel average misorientation maps. We show that only the latter allow a reliable separation of the bainitic and ferritic phase. The kernel average misorientation threshold value that separates both constituents is determined by an algorithm that searches for the smoothness of the boundaries between them.
贝氏体被认为在低合金相变诱发塑性钢中对亚稳奥氏体的化学和力学稳定性起着重要作用。因此，为了理解和改善材料性能，定位和量化贝氏体相很重要。为此，采用了基于电子背散射衍射的取向显微镜。这里的主要困难在于区分贝氏体铁素体和铁素体，因为两者都具有体心立方晶体结构。它们之间最重要的区别是贝氏体相中出现了相变诱发几何必要位错。为了确定具有较大几何必要位错密度的区域，研究了以下取向显微镜图：图案质量图、晶粒参考取向偏差图和核平均取向差图。我们表明，只有后者能够可靠地分离贝氏体相和铁素体相。分离这两种组分的核平均取向差阈值由一种搜索它们之间边界平滑度的算法确定。
