摘要
研究了15Cr系亚共晶高铬铸铁超固相线液相烧结的制备工艺,利用光学显微镜和扫描电镜对合金的微观组织及冲击试样断口进行了观察和分析,探讨了烧结温度对高铬铸铁组织和力学性能的影响;并采用计算机定量分析金相组织,确定了组织与性能的相关性.研究结果表明,超固相线液相烧结制备的15Cr系亚共晶高铬铸铁相对致密度达99%以上.与普通铸造高铬铸铁相比,烧结制品碳化物外形圆润,呈短杆状均匀分布.随烧结温度的升高,基体晶粒和碳化物逐渐长大,合金力学性能呈现先升后降的规律;1210℃×1.5 h烧结制品的冲击韧性和抗弯强度达到最大值11.3 J/cm^2和2506.8 MPa.试样的冲击断裂为准解理断裂机制,韧性较普通铸造试样大幅提高.烧结温度主要通过影响试样组织中碳化物数量、分布、形态以及尺寸,来影响合金力学性能.碳化物体积分数是影响高铬铸铁硬度的主要因素.
The preparation process for supersolidus liquid phase sintering of 15Cr series hypoeutectic high-chromium cast iron was studied.The microstructure and impact specimen fractures of the alloy were observed and analyzed by an optical microscope and a scanning electron microscope.The effect of sintering temperature on the microstructure and mechanical properties of high-chromium cast iron was discussed.Quantitative analysis of the metallographic structure was performed using a computer software to determine the correlation between microstructures and performance.The results show that the relative density of 15Cr-based hypoeutectic high chromium cast iron prepared by supersolidus liquid phase sintering is of more than 99%.Compared with ordinary cast high-chromium cast iron,the carbide of the sintered one is of a short rod shape and evenly distributed in its matrix.With the increase of sintering temperatures,both the grains of the matrix and carbides gradually grew up,and the mechanical properties of the alloy increased firstly and then declined gradually.The impact toughness and bending strength reached the maximum of 11.3 J/cm^2 and 2506.8 MPa as the alloy was sintered at 1210℃for 1.5 h.The impact fracture of the specimen is of a quasi-cleavage fracture mechanism,and the toughness is greatly improved when compared with the common cast specimens.The sintering temperature mainly affects the alloy's mechanical properties by changing the volume fraction,distribution,morphology and size of the carbides in the microstructure.The hardness of the sintered cast iron has close relationship with carbide volume fraction.
作者
肖平安
肖璐琼
顾景洪
李忠涛
卢瑞青
石管华
XIAO Ping′an;XIAO Luqiong;GU Jinghong;LI Zhongtao;LU Ruiqing;SHI Guanhua(College of Materials Science and Engineering,Hunan University,Changsha410082,China)
出处
《湖南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2019年第12期58-64,共7页
Journal of Hunan University:Natural Sciences
基金
国家自然科学基金资助项目(751229073)~~
关键词
高铬铸铁
超固相线液相烧结
金相分析
力学性能
high chromium cast iron
supersolidus liquid phase sintering
metallographic analysis
mechanical property
作者简介
通讯联系人:肖平安(1962—),男,湖南长沙人,湖南大学教授,博士生导师,E-mail:changcluj@163.com。
