高钨高速钢中碳化物结构及界面特征  

Crystal structure and interface feature of carbide in high speed steel with high tungsten content

作　　者：徐流杰[1,2] 周鹤[3] 魏世忠[1] 

机构地区：[1]河南科技大学摩擦学与材料防护教育部工程研究中心,河南洛阳471003 [2]有色金属共性技术河南省协同创新中心,河南洛阳471023 [3]河南科技大学材料科学与工程学院,河南洛阳471023

出　　处：《材料热处理学报》2016年第7期123-128,共6页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51171060);河南省高等学校青年骨干教师资助计划(2012GGJS-072);长江学者和创新团队发展计划(IRT1234)

摘　　要：采用铸造法制备了含钨10%的高钨高速钢,利用XRD、SEM、HRTEM、EDAX研究了高钨高速钢中碳化物的类型、成分、结构及其界面晶体学特征。结果表明:高钨高速钢中的碳化物有两种,一种是凝固过程中析出的鱼骨状共晶碳化物,别一种为回火过程中析出的颗粒状二次碳化物,二者均为面立方晶体结构的M_6C。共晶M_6C的分子式可表达为(Fe_(0.55)W_(0.30)Cr_(0.08)Mo_(0.07))_6C,二次M_6C中的合金元素含量与之基本相同。共晶M_6C型碳化物与基体间存在晶体学关系,在铸态组织中,M_6C的(111)晶面平行于铁素体(110)晶面,即M_6C(111)//α-Fe(110),而高速钢回火后,基体组织转变成马氏体(M)与残留奥氏体,界面的晶体学位向关系变为:M_6C(111)//M(020)。二次M_6C型碳化物与马氏体界面为良好的冶金结合,M_6C的(133)晶面与马氏体的(101)晶面夹角约为140°。部分二次M_6C可以依附于共晶M_6C析出,二者的(202)晶面共格。High speed steel with 10% tungsten content was prepared by casting method. The type, composition, crystal structure and crystallographic feature of interface of the carbides were analyzed by means of X-ray diffractomcter （XRD） , scan elcctron microscopy （SEM）, high resolution transmission electron microscopy （HRTEM） and energy dispersive X-ray analysis （EDAX）. The results show that there are two kinds of carbides in the steel. One is fishbone-like eutectic carbide crystallizing during solidification, another is granular secondary carbide precipitating during tempering. The two kinds of the carbides are all M6C with face-centered cubic crystal structure. The formula of eutectic M6C carbide can be expressed as （Fe0.55W0.30Cr0.08Mo0.07）6C, and the alloy element contents in secondary M6C carbide are nearly the same as that of cutectic M6C carbide. There are crystallographic relationships between eutectic M6C and matrix. For the as-cast microstructure, M6C （ 111 ） planes parallel to ct-Fe （ 110）. Nevertheless, the crystallographic orientation at the interface is transformed into M6C （ 111 ） planes parallel to martersite（020） in the tempered high speed steel. The secondary M,,C is metallurgically bonded to the matrix, and the angle between M6C （133） and martersite （101） is about 140°. Besides, some secondary M6C can precipitate attaching to eutectic M6C, which is perfectly coherent with eutectic M6C at （202） plane.

关 键 词：钨 高速钢 M6C碳化物 界面 

分 类 号：TG142.4[一般工业技术—材料科学与工程]