铸态304L奥氏体不锈钢等径角挤压变形研究

 研究了铸态304L奥氏体不锈钢在等径角挤压(ECAP)变形过程中显微组织的演变过程。结果表明，经4道次剪切变形后树枝晶破碎、原始粗大晶粒碎化。显微组织的变化过程可归纳为：原始粗晶粒→晶粒被滑移带分割→位错发展形成高密度位错墙，与滑移带共同作用形成胞块结构→应变增加形成层片状界面→形成大角度晶界的细小晶粒。表明铸态304L奥氏体不锈钢经ECAP变形后塑性变形机制主要由滑移完成。

Equal Channel Angular Pressing Deformation of As-Cast 304L Austenitic Stainless Steel

The microstructure evolution of as cast 304L austenitic stainless steel during equal channel angular pressing is investigated. Experimental results show that dendritic crystals break are broken and original coarse grains are refined after the fourth pass pressing. The process of grain refinement can be described as follows: original coarse grains→grains are divided by some slip bands→dislocations form dense dislocation walls which interact with slip bands and form cell blocks→with increasing the strain, lamellar boundarys have been formed→fine grains form with large angular grain boundary. The deformation mechanism of as cast 304L austenitic stainless steel is slipping during equal channel angular pressing.