论文部分内容阅读
以Q215钢为试验对象,通过在粉末法渗硼过程中施加4 A电流的交流电场,分别在873,973和1073 K进行不同保温时间(0~360 min)的交流电场增强粉末法渗硼,并与常规粉末法渗硼对比分析.结果表明:电场增强渗硼的渗层在基本形态上与常规渗硼一致,以齿状楔入基体,但在相结构方面存在差异,前者渗硼保温超过30 min即为单相Fe2B,后者在各条件下均为双相FeB+Fe2B,且电场增强渗硼层的表层硬度低于常规渗硼的;电场增强渗硼速度显著快于常规渗硼;渗层生长与渗硼时间的抛物线关系说明电场增强渗硼也是一种扩散控制工艺;电场增强渗硼的原子扩散激活能为24.66 kJ/mol,远低于常规渗硼的扩散激活能166.30 kJ/mol.从交流电场提高试样内部空位浓度及其迁移能力方面初步分析其加速渗扩及影响渗层相结构的机制.
Q215 steel was used as the test object to enhance boron powder by AC electric field with different holding time (0 ~ 360 min) at 873, 973 and 1073 K respectively by AC electric field with 4 A current during boronizing by powder method. The results show that the infiltration layer enhanced by electric field is consistent with the conventional boronization in the basic morphology and wedged into the matrix by dentate, but there is difference in the phase structure. The former is infiltrated by boron for more than 30 minutes That is, single-phase Fe2B, the latter under both conditions are dual-phase FeB + Fe2B, and the surface hardness of the electric field enhanced boronizing layer is lower than conventional boronizing; electric field enhanced boronizing rate significantly faster than conventional boronizing; The parabolic relationship between growth and infiltration time shows that electric field enhanced boronization is also a diffusion control process. The atomic diffusion activation energy of electric field enhanced boronization is 24.66 kJ / mol, which is much lower than that of conventional boronizing diffusion activation energy of 166.30 kJ / mol. The mechanisms of accelerating infiltration and affecting the phase structure of infiltrated layer were analyzed preliminarily from the aspects of increasing the concentration of vacancies inside the sample and its migration ability by AC electric field.