U71Mn钢轨铣削用PVD-TiAlN涂层刀片失效分析  

Failure Analysis of PVD-TiAlN Coated Tools for Rail Milling

作　　者：王梦超[1] 王丽君 陈辉[1] WANG Meng-chao;WANG Li-jun;CHEN Hui(Southwest Jiaotong University,Chengdu 610031,China;Chengdu Vocational&Technical College of Industry,Chengdu 610218,China)

机构地区：[1]西南交通大学,成都610031 [2]成都工业职业技术学院,成都610218

出　　处：《表面技术》2020年第3期300-308,共9页Surface Technology

基　　金：国家重点研发计划项目(2017YFB0305905)。

摘　　要：目的分析研究PVD-TiAlN涂层刀片铣削钢轨(U71Mn)后的失效行为,确定涂层刀片铣削U71Mn的磨损机制及失效机理,为进一步改进铣削U71Mn用涂层刀片的使用性能提供指导。方法采用多弧离子镀技术在硬质合金基体刀片上制备了厚度约2.13μm的TiAlN涂层,通过扫描电子显微镜、能谱仪、金相检测仪等仪器,检测了刀片基体和涂层的显微组织和金相结构。采用立式铣床对U71Mn进行铣削,通过扫描电子显微镜观察失效刀片前刀面、刃口和后刀面的微观形貌,结合能谱仪微区成分分析,确定涂层刀片的磨损机制和失效机理。结果通过金相检测仪和扫描电子显微镜检测,YG10细晶粒硬质合金基体无明显组织缺陷。采用多弧离子镀制备的涂层膜基结合力等级为HF1,具有较好的膜基结合强度。失效刀片的刃口处存在贯穿前刀面、刃口和后刀面的裂纹,并且刃口区域的裂纹内部有被加工材料的填充物。后刀面裂纹尖端有涂层的微崩裂,前刀面的磨损带边界较后刀面磨损带边界平齐。刃口附近的涂层表面上出现了相互交联的裂纹。失效刃口多出现锯齿形缺口,缺口内部有大量的碎屑填充物,缺口对应的后刀面处分布着深浅不同的沟槽。磨损的刃口上粘接有大量的被加工材料。结论刀片的磨损机制有磨粒磨损、粘接磨损和氧化磨损。另外,刃口的崩裂在刀片失效过程中也扮演着重要角色,崩裂的缺口会为硬质颗粒提供存储空间,从而加剧磨料磨损,在多种磨损机制共同作用下,刀片刃口最终被磨耗而失效。可通过提高基体的强韧性、合理的刃口设计、改善涂层的韧性和结合力、提高涂层的抗氧化性等方面,提高涂层刀片铣削U71Mn的性能。In order to provide guidance for further improving the performance of coated tools for rail(U71 Mn)milling,the failure behavior of PVD-TiAlN coated tools for U71 Mn milling was analyzed.Simultaneously,the wear mechanism and failure mechanism of the coated tools were determined.The TiAlN coating with a thickness of about 2.13μm was prepared on cemented carbide tools by multi-arc ion plating technology.The substrate and coating of the tools were detected by scanning electron microscope(SEM),energy dispersive spectroscopy(EDS)and metallography.Vertical milling machine with the PVD-TiAlN coated tools was used to mill U71 Mn.SEM was used to observe the micro morphology of the front surface,edge and flank surface of the failed tools.The wear mechanism and failure mechanism of the coated tools were determined by EDS micro-zone composition analysis and SEM micro morphology analysis.Through metallographic and SEM tests,YG10 fine grain cemented carbide had no obvious structural defects.The film-substrate adhesion strength of the coating prepared by multi-arc ion plating was HF1,which indicated that the film-substrate adhesion strength was good.There were cracks through the front surface,edge and flank surface of the failed tools,but there were fillings of processed materials inside the cracks only in the edge area.The coating on the crack tip of the flank surface of failed tools was slightly broken.The wear zone boundary of the rake face is flatter than the wear zone boundary of the flank face.Cross cracks appeared on the coating surface near the edge.There were many jagged edges with many fragmental fillings at the edges of the failed tools.Many grooves of different depth were distributed the flank surface corresponding to these gaps.The worn edge was covered with a large amount of processed material.The wear mechanism of tools included abrasive wear,adhesive wear and oxidation wear.In addition,the collapse of the edge also played an important role in the failure process of the coated tools.The cracks provided storage sp

关 键 词：TIALN涂层 U71Mn 涂层刀片 失效分析 磨损机制 失效机理 

分 类 号：TG174.4[金属学及工艺—金属表面处理] TH117.7[金属学及工艺—金属学]