H13钢表面硼铬复合渗层的冷热循环裂纹扩展特性  

Cold and Hot Cyclic Crack Growth Characteristics of Boron-chromium Composite Infiltration Coating on H13Steel Surface

作　　者：赵小雨 王华君[1] 高野 汪学阳[1] 李科举 Zhao Xiaoyu;Wang Huajun;Gao Ye;Wang Xueyang;Li Keju(School of Materials Science and Engineering,Wuhan University of Technology)

机构地区：[1]武汉理工大学材料科学与工程学院,武汉430070

出　　处：《特种铸造及有色合金》2020年第6期647-649,共3页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(51475346);武汉理工大学优秀学位论文培育资助项目(2017-YS-006)。

摘　　要：通过TRD盐浴处理方法在H13钢表面分别制备出硼铬复合渗覆层和单渗硼覆层。在试样上切出预制裂纹并在20~650℃下分别进行热疲劳循环试验,采用电子探针显微分析仪观察预制裂纹尖端的裂纹扩展情况,并通过点扫描分析表面氧化团形成原因。结果表明,硼铬复合渗层表面氧化现象更轻微,扩展的裂纹更少,说明硼铬复合渗层比单渗硼层拥有更好的抗疲劳性能。渗硼试样的裂纹扩展是氧化撕裂和应力撕裂的共同作用导致的;硼铬复合渗试样的裂纹扩展主要原因是应力撕裂。Boron-chromium composite infiltration coating and the single boronized coating were prepared on H13 steel by TRD salt bath treatment.The precracks were cut on the samples and each sample was subjected to a thermal fatigue test with cold and hot cycle at 20~650℃.The tip crack size of the sample was observed and measured by the EMPA,and the mechanism for the formation of oxide cluster on the surface was analyzed by point scanning.The results show that there exsit less oxidation phenomenon and fewer crack growth on the surface of the boron-chromium composite infiltrated layer sample,which shows that boron-chromium composite infiltration coating has better oxidation resistance than single boronized coating.The crack growth of boronized samples is attributed to the combination of oxidative tearing and stress tearing,while the crack growth of the boron-chromium composite samples is mainly attributed to stress tearing.

关 键 词：TRD盐浴 硼铬覆层 热疲劳 H13钢 铝合金压铸 

分 类 号：TG156.8[金属学及工艺—热处理] TG249.2[金属学及工艺—金属学]