协变相变组织原始奥氏体取向重构及其在奥氏体孪晶中的应用  

Prior austenite orientation reconstruction of coherently transformed products and its application on austenite twinning

作　　者：王智权[1,2,3] 宋婷婷 由洋 王学林[3] 尚成嘉 刘锟 陈斌 WANG Zhi-quan;SONG Ting-ting;YOU Yang;WANG Xue-lin;SHANG Cheng-jia;LIU Kun;CHEN Bin(Sheet Metal Research Institute,Shougang Research Institute of Technology,Beijing 100043,China;Beijing Engineering Research Center of Energy Steel,Beijing 100043,China;Collaborative Innovation Center of Steel Technology,University of Science and Technology Beijing,Beijing 100083,China;Hadal Science and Technology Research Center,Shanghai Ocean University,Shanghai 201206,China;ASSAB Tooling Beijing Co.,Ltd.,Beijing 214429,China)

机构地区：[1]首钢技术研究院薄板研究所,北京100043 [2]北京市能源用钢工程技术研究中心,北京100043 [3]北京科技大学钢铁共性技术协同创新中心,北京100083 [4]上海海洋大学深渊科学技术研究中心,上海201206 [5]壹胜百模具(北京)有限公司,北京214429

出　　处：《工程科学学报》2018年第8期945-953,共9页Chinese Journal of Engineering

摘　　要：基于电子背散射衍射（EBSD）技术,利用极射赤面投影图,提出了一种不依赖于残余奥氏体,对协变相变产物的原奥取向进行重构的简易方法.计算结果表明,利用铁素体的{110}α极图中三个贝恩组的交点可以成功重构出原始奥氏体取向,并且精度可达2°;同时,该方法还可以对局部微区或者变体选择很严重的原奥取向进行重构,误差仍可控制在2°之内,具有其他重构方法无可比拟的优点.位向关系具体种类并不影响对原奥取向的重构,采用该方法进行原奥取向重构时不需要预先知道具体的位向关系,并且适用于位向关系处在K-S与N-W关系之间的所有协变相变过程.通过运用该方法重构原奥取向,本文研究了高温奥氏体化过程中的奥氏体行为.研究发现当采用较高的温度奥氏体化时会出现奥氏体孪晶,奥氏体孪晶的出现与奥氏体化温度有关.High-angle grain boundaries and martensite/austenite（M/A） constituents are two critical factors that contribute to low impact toughness in metals.The generation mechanism of the high-angle grain boundaries is closely related to the crystallography of the transformed products,which are transformed by prior austenite.Austenite undergoes phase transformation when cooled to ambient temperature and cannot be retained.During coherent phase transformation,variant pairs,from which the high-angle grain boundaries originate,are transformed.Variant selection is a common phenomenon in coherent phase transformation.The properties of the prior austenite grain,such as its shape,size,orientation,texture,and particularity of formation,will affect the subsequent phase transformation dramatically,and the variant pairs are accordingly introduced.However,it is impossible to evaluate this effect when the prior austeniteorientation is unclear.Hence,the orientation needs to be reconstructed.In this article,a simple method of reconstructing the prior austenite orientation during coherent phase transformation is proposed by employing the { 110}αstereographic projection on the basis of electron backscatter diffraction（EBSD） measurements.Retained austenite is not necessary when applying this methodology.The results show that the prior austenite orientation is well reconstructed with superior precision of below 2°.This is especially applicable when strong variant selection occurs or when reconstructing a tiny part of the prior austenite grain.The specific unknown orientation relationship（OR） between prior austenite and ferrite has a little effect on the reconstruction process,averting complicated calculations of this specific unknown OR.It is still possible to reconstruct the austenite orientation when the actual OR is not accessible.Moreover,it can be employed to all the coherently transformed products that maintain an OR from K-S OR to N-W OR to the prior austenite grain.A specific example in which this method is adopted is g

关 键 词：原始奥氏体 协变相变 取向重构 极图 变体 奥氏体孪晶 

分 类 号：TG142.3[一般工业技术—材料科学与工程]