共晶灰铸铁的结晶动力学  

Crystallization kinetics of eutectic gray cast iron

作　　者：杨忠[1] 王金炜[1] 冯云鹏[2] 杨雨[2] 

机构地区：[1]西安工业大学材料与化工学院,陕西西安710021 [2]北京特种车辆研究所,北京100071

出　　处：《材料热处理学报》2017年第4期152-158,共7页Transactions of Materials and Heat Treatment

基　　金：基金项目:高蠕化率蠕铁气缸盖成形技术研究(30105090201)

摘　　要：结合数字光学显微镜、扫描电镜(SEM)、高分辨三维X射线衍射、热分析和高温液淬的方法研究共晶灰铸铁的凝固过程和组织演变规律,深入分析石墨的长大动力学及三维连通特征。结果表明:共晶灰铸铁中的石墨结晶初始形貌为球状,异质形核核心为MnS,尺寸为1~2μm;共晶反应开始时石墨发生变异,长成细小片状石墨,并在共晶团内长大,随后相邻共晶团内的石墨通过中间的液相生长在一起,连接成更大的石墨,共晶反应结束时,大部分石墨在三维上连接在一起,连通率为88.87%;共晶灰铸铁结晶时,石墨长度与时间的关系为、L=-390.56+555.32(1-e^(-t/34.52)),石墨含量与时间的关系为、C=-17.24+27.02(1-e^(-t/41.57))。The solidification process and microstructure evolution of eutectie gray cast iron were studied by means of digital optical microscope, scanning electron microscopy （SEM）, high resolution three-dimensional X ray diffraction, thermal analysis and high temperature liquid quenching, besides growth kinetics and three-dimensional connectivity of the graphite were analyzed deeply. The results show that the initial shape of graphite in eutectic gray cast iron is spherical, and the nucleation core of the graphite is mainly MnS, which size is less than 2 μm; the spherical graphite mutates into fine flake graphite when the eutectic reaction starts, and the fine flake graphite grows up in the eutectic ceils, then the graphite in the adjacent euteetic cells grows together through the liquid phase forming larger graphite, most of the graphite connects together in three dimensions at the end of eutectic reaction, the connection rate is 88.87% ; when the eutectic gray cast iron crystallize, the relationship between the length of graphite and the time is, L = - 390.56 ＋ 555.32 （ 1 - e -^-t/34.52 ） , and the relationship between the content of graphite and the time is, C = - 17.24 ＋ 27.02（ 1 - e -^-t/41.57 ）.

关 键 词：共晶灰铸铁 组织转变 石墨形核 石墨生长 三维连通率 

分 类 号：TG143.2[一般工业技术—材料科学与工程]