摘要
以45钢和42CrMo钢为材料,对比研究了合金元素对离子碳氮共渗化合物层生长动力学的影响。利用光学显微镜、显微硬度计和X射线衍射仪对化合物层的显微组织、厚度、硬度及物相进行了测试和分析。结果表明,相同工艺条件下,42CrMo钢表面形成的化合物层厚度比45钢薄,但有效硬化层较厚,表面硬度高且截面硬度梯度较为平缓;随着保温时间的延长,45钢离子碳氮共渗后化合物层中的主要物相发生了γ'-Fe4(C,N)→ε-Fe2-3(C,N)的转变,而在42CrMo钢表层则无该转变,但出现了CrN、CrC及Mo2(C,N)相;动力学分析表明42CrMo钢形成化合物层的扩散激活能为66.95kJ/mol,接近45钢27.89kJ/mol的2.5倍,同时分析了合金元素对活性C、N原子扩散的影响机理。
45 and 42CrMo steel were selected as the tested materials,the effect of alloying elements on growth kinetics of plasma nitrocarburized layer was investigated. The microstructure,thickness,hardness and phases of the nitrocarburized layers were analyzed by means of optical microscopy,X-ray diffraction and microhardness tester. The results show that the thickness of compound layer of the42CrMo steel is thinner than that of 45 steel under the same condition,while 42CrMo steel owns thicker case depth,higher surface hardness and gentler cross-section hardness gradient. The dominated phase transforms from γ'-Fe4( C,N) to ε-Fe2- 3( C,N) phase with the increasing of time for 45 steel,while this transformation is not observed for 42CrMo steel,though Cr N,Cr C and Mo2( C,N) phases are clearly visible. Meanwhile,it is calculated that the diffusion activation energy( Q) of forming compound layer is 66. 95 k J / mol for42CrMo steel,which is almost 2. 5 times that of 27. 89 k J / mol for 45 steel. Moreover,the mechanism of alloying elements on the diffusion process of active C and N atom is analyzed.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2015年第S1期203-207,共5页
Transactions of Materials and Heat Treatment
基金
江苏高校优势学科建设工程项目
江苏省科技成果转化项目(BA2013078)
