13Cr4Mo4Ni4VA钢复合硬化层的表征研究  

Characterization Study of Duplex-hardened 13Cr4Mo4Ni4VA Steel

作　　者：江志华[1] 李春志[1] 张建国[2] 金建军[1] 佟小军[1] 王晓震[1] 

机构地区：[1]北京航空材料研究院,北京100095 [2]西北工业大学材料科学与工程学院,西安710072

出　　处：《航空材料学报》2015年第5期7-12,共6页Journal of Aeronautical Materials

摘　　要：对渗碳硬化13Cr4Mo4Ni4VA钢进行渗氮处理后形成复合硬化层,采用光学显微镜、扫描电镜、X射线衍射、透射电镜、高分辨电镜、电子探针及显微硬度测试等方法对复合硬化层进行表征。结果表明,复合硬化13Cr4Mo4Ni4VA钢渗层碳氮浓度呈梯度分布,从表面到心部组织性能也呈梯度变化,表现出异于传统硬化工艺的组织结构特性。复合硬化层为双层硬化结构,渗氮层组织优异,少无沿晶化合物,析出细小的片状的Mo2N、周期性层状分布的Mo2C以及Cr2(C,N)等合金碳(氮)化合物,在析出相沉淀硬化和碳氮原子固溶强化共同作用下,使复合硬化层表面硬度达到超硬化(>70HRC),有效硬化层维持很大的层深,具有优异的硬度梯度及残余压应力场。Duplex thermochemical processing of 13Cr4Mo4Ni4 VA steel was carried out,which involves carburizing（ followed by hardening and tempering） and then nitriding. Optical microscopy,scanning electron microscopy,X-ray diffraction,transmission electron microscopy,high resolution transmission electron microscopy,electron probe micro-analyzer,and microhardness tester were used to study the characterization of the duplex-hardened 13Cr4Mo4Ni4 VA steel. Distinct from traditional case hardening process,carbon and nitrogen introduced into the matrix during duplex thermochemical process created duplex case structure with selected solubility gradient of carbon and nitrogen,comprising of nitrided layer and then carburized layer. In nitrided layer,very few intergranular nitrides were found,fine precipitates of Cr2（ C,N）,Mo2 C with lamellar microstructure and angstrom-scale flake of Mo2 N formed inside the tempered martensite substrate。Solid solution strengthening by carbon and nitrogen interstitially dissolved and precipitation hardening by fine precipitates caused favorable hardness gradient of superior surface hardness（ 70HRC） and deeper hardened layer,and excellent distribution of residual compressive stresses were produced in duplex hardening case.

关 键 词：13Cr4Mo4Ni4VA钢 双层硬化结构 Cr2(C N) 片状Mo2N 层状结构Mo2C 表面超硬化(〉70HRC) 硬度梯度 残余压应力场 

分 类 号：TG161.8[金属学及工艺—热处理]