Cr含量对白口铸铁碳化物类型转变机理的影响  

Effect of Cr Content on Transformation Mechanism of Carbide Types in White Cast Iron

作　　者：谢文玲[1] 李秀兰[1] 郭翠霞[1] 胡勇[1] 

机构地区：[1]四川理工学院机械工程学院,四川自贡643000

出　　处：《铸造技术》2016年第12期2629-2631,2635,共4页Foundry Technology

基　　金：国家自然科学基金青年基金资助项目(51301115);四川理工学院人才引进项目资助(2013RC06);材料腐蚀与防护四川省重点实验室资助项目(2015CL06)

摘　　要：从碳化物形核和碳化物长大两方面研究Cr含量对白口铸铁碳化物类型及析出机理的影响。研究表明:Cr的加入使白口铸铁中的碳化物类型发生如下转变:Fe_3C→(Fe,Cr)_3C→(Fe,Cr)_3C+(Fe,Cr)_7C_3→(Fe,Cr)_7C_3。Cr改变了铁液中碳化物形核的热力学条件,Cr原子可置换铁液中的Fe原子形成(Fe,Cr)_3C碳化物,从而导致碳化物晶体结构发生畸变。Cr含量越高,畸变程度越严重,碳化物晶体结构由M_3C转变为M_7C_3型碳化物的临界含Cr量为10%。随Cr量的增加,评价固液微观结构的Jackson因子增加,碳化物生长速度变慢,因此,碳化物断网趋向增加,碳化物形貌从连接成网络的蜂窝状变为杆状。The effect of Cr content variation in white cast iron on carbides types and precipitation mechanism were studied from carbides nucleation and growthing. The results show that Cr addition makes carbides type change as follows： Fe3C→（Fe, Cr）3C→（Fe,Cr）3C＋（Fe,Cr）TC3→（Fe,Cr）7C3. Thermodynamic condition of carbides nucleation in iron liquid is changed owing to Cr additions, Cr atom can displace Fe atom from iron liquid to form （Fe,Cr）3C carbides, which led to the distortion of carbides crystal structure. The higher the Cr content is, the more serious the carbide lattice distortion degree is, the critical Cr content of carbides crystal structure transition from M3C to M7C3 is 10%. With the increase of Cr addition, Jackson factor of evaluating the microstructure of solid-liquid increases, the carbide growthing rate becomes slow, so carbides fracture network tends to increase and carbides morphology vary from network honeycomb to rod shaped.

关 键 词：白口铸铁 CR 碳化物 转变机理 

分 类 号：TG143.1[一般工业技术—材料科学与工程]