45钢直流电场增强粉末法硼铝共渗特性  

Characteristics of direct current field enhanced pack boron-aluminizing of 45 steel

作　　者：任中花 谢飞 潘建伟[3] Ren Zhonghua;Xie Fei;Pan Jianwei(School of Materials Science and Engineering,Changzhou University,Changzhou Jiangsu 213164,China;Key Laboratory of Materials Surface Engineering of Jiangsu Province,Changzhou University,Changzhou Jiangsu 213164,China;Huaide College,Changzhou University,Changzhou Jiangsu 213016,China)

机构地区：[1]常州大学材料科学与工程学院,江苏常州213164 [2]常州大学江苏省表面技术重点实验室,江苏常州213164 [3]常州大学怀德学院,江苏常州213016

出　　处：《金属热处理》2022年第12期188-196,共9页Heat Treatment of Metals

基　　金：国家自然科学基金(51171032)

摘　　要：采用不同铝粉含量(0%~1.5%)的硼铝共渗剂对45钢于750℃进行直流电场增强粉末法硼铝共渗,并与相应常规渗扩及直流电场增强单一渗硼对比。通过X射线衍射、光学显微镜以及显微硬度测试等方法,观察分析位于直流电场中不同位置试样渗层的相结构、显微组织及硬度分布。结果表明,直流电场对粉末法渗硼、硼铝共渗均有显著促渗作用;直流电场增强渗扩渗层的形成特性不仅与试样位置及渗扩面位向有关,还与渗剂中铝粉含量有关,渗剂中铝粉含量由0增加至1.5%,负极试样面向正极侧与中间试样面向正极侧的渗层厚度先增加后降低,中间试样面向负极侧渗层厚度先缓慢增加然后大幅度增加,正极试样面向负极侧渗层厚度先增后降再增加。铝粉含量为0时,正极试样面向负极侧和中间试样面向负极侧渗层均为“锯齿状”单相Fe_(2)B,负极试样面向正极侧和中间试样面向正极侧由“锯齿状”FeB+Fe_(2)B构成。铝含量为0.3%时,各渗层均由双相“锯齿状”(Fe,Al)B和(Fe,Al)_(2)B构成;渗层呈“锯齿状”特征时,硬度峰值在1400~1900 HV0.025。当铝粉含量≥0.5%时,由负极向正极,渗层“锯齿状”特征逐渐消失,各试样渗层表层逐步出现KAlF_(4)、AlF_(3)及Fe_(3)Si等相,渗层硬度显著降低,硬度峰值为450~1400 HV0.025。Direct current field enhanced pack boron-aluminizing(DCFEPBA)was carried out on 45 steel at 750℃by using pack agent with content of aluminum powder varied from 0 to 1.5%,and compared with the corresponding conventional diffusion and direct current field enhanced boronizing.The phase structure,microstructure and hardness distribution of the specimen case at different positions in the direct current field were observed and analyzed by means of X-ray diffraction,optical microscopy and microhardness test.The results show that the direct current field has a significant enhancing effect on both pack boriding and pack boron-aluminizing.The formation characteristics of the direct current electric field enhanced case are not only related to the position of the specimen and the orientation of the diffusion surface,but also to the content of aluminum powder in the penetrant.When the content of aluminum powder in the penetrant increases from 0 to 1.5%,the thickness of the case of the cathode specimen facing the anode,and that of the intermediate specimen facing the anode increase first and then decrease;While the thickness of the case of the intermediate specimen facing the cathode increases slowly first and then increases significantly,and that of the anode specimen facing the cathode increases first,then decreases,and then increases.When the aluminum content is 0,the case of the anode specimen facing the cathode side and that of the intermediate specimen facing the cathode side are both serrated single-phase Fe_(2)B,and that of the cathode specimen facing the anode side and that of the intermediate specimen facing the anode side are composed of“serrated”FeB+Fe_(2)B.When the aluminum content is 0.3%,each case is composed of two-phase“serrated”(Fe,Al)B and(Fe,Al)_(2)B;and when the case is serrated,the peak hardness is 1400-1900 HV0.025.When the aluminum powder content is≥0.5%,the“serrated”feature of the case gradually disappears from the cathode to the anode,the KAlF_(4),AlF_(3),and Fe_(3)Si phases gradually

关 键 词：粉末法硼铝共渗 直流电场 相结构 组织 显微硬度 

分 类 号：TG156.8[金属学及工艺—热处理]