梯度结构半固态9Cr18不锈钢的制备与显微组织演变  

Fabrication of Gradient Semi-solid 9Cr18 Stainless Steel and the Microstructure Evolution

作　　者：王永金 张应超 宋仁伯[1] WANG Yongjin;ZHANG Yingchao;SONG Renbo(School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学材料科学与工程学院,北京100083

出　　处：《材料导报》2021年第2期2120-2124,共5页Materials Reports

基　　金：中国博士后科学基金(2019M650482);中央高校基本科研业务费(FRF-TP-18-039A1)。

摘　　要：基于Gleeble3500热模拟试验机设计了半固态触变锻造成形装置,通过触变锻造工艺制备了9Cr18不锈钢制件,研究其显微组织结构和演变特征。研究结果表明,半固态触变成形装置能够实现9Cr18半固态坯料成形。在触变锻造成形过程中,固相骨架破碎后,半固态坯料表现出触变特性,载荷随着变形的进行而下降。9Cr18触变制件变形区呈现梯度结构的显微组织特征。触变制件边部存在明显的液/固分界层。分界层外侧为液相凝固形成的共晶组织;分界层内侧主要为固相颗粒。9Cr18触变制件具有独特的组织演变规律,其内部主要为具有良好塑性变形能力的奥氏体组织,表层存在大量的M 7C 3共晶碳化物,二者共同保证了9Cr18不锈钢触变制件具有“外硬内韧”的特征。In this paper, a semi-solid thixoforging set-up was designed based on Gleeble3500 thermomechanical machine. 9Cr18 thixoforging component was fabricated and the microstructure evolution was investigated. The results showed that the 9Cr18 semi-solid billet could demonstrated thi-xotropic behavior after the breakdown of solid skeleton and load decreased with the deformation during thixotropic stage. Gradient microstructure could be obtained for the 9Cr18 thixoforging specimen. An obvious solid/liquid interface existed near the edge area of thixoforging specimen. Eutectic structure with plenty of carbide could be seen outside the solid/liquid interface. Solid particles were mainly retained at the inner area. 9Cr18 thixoforging specimen demonstrated unique microstructure evolution. The solid particles at the inner area mainly showed austenite microstructure with excellent deformation behavior, while the hard M 7C 3 carbides existed at surface eutectic layer. This microstructure characterization contributed to the properties of tough center and hard surface.

关 键 词：9Cr18不锈钢 半固态 触变锻造 梯度结构 组织演变 

分 类 号：TG142.1[金属学及工艺—金属材料]