摘要
通过对M390粉末冶金刀具钢材料进行扫描电子显微组织观察、X射线衍射分析以及原位拉伸试验,研究了M390粉末冶金刀具钢微观组织结构和拉伸断裂行为,并分析了碳化物在粉末冶金刀具钢断裂过程中的作用。研究发现:M390粉末冶金刀具钢的显微组织是由基体和分布在基体上的碳化物两部分组成,其中基体组织为铁素体,碳化物则包括富铬等合金元素的M_(7)C_(3)和M_(23)C_(6)型碳化物,这些碳化物相严重影响M390粉末冶金刀具钢的断裂。随着外加载荷增加,分布在基体上的碳化物相提前开裂,形成裂纹源,裂纹呈现穿过或绕过碳化物的形式扩展,在进一步加载的情况下,裂纹处形成应力集中,导致基体发生脆性断裂。碳化物相成为M390粉末冶金刀具钢断裂过程的薄弱环节。试样断口呈现脆性断裂特征,并包含少量韧窝,且韧窝中存在第二相质点,即碳化物。
The microstructure and tensile fracture behavior of M390 powder metallurgy tool steels were investigated by scanning electron microscopy,X-ray diffraction analysis,and in-situ tensile test,and the effect of the carbides on the fracture process of the powder metallurgy tool steels was analyzed.The results show that,the microstructures of the M390 powder metallurgy tool steels are composed of the ferrite matrix and carbides as M_(7)C_(3) and M_(23)C_(6) with the chromium-rich alloy elements.These carbide phases seriously affect the fracture processes of M390 powder metallurgy tool steels.With the increase of the applied load,the cracks are firstly presented at the carbide phases distributed on the matrix,then propagate through or bypass the carbides.With the further increase of the applied load,the stress concentration at the tip of cracks causes the brittle fracture of the matrix.The carbide phases become the weakest in the fracture process of the M390 powder metallurgy tool steels.The fracture of the tool steel samples shows the brittle fracture characteristics and contains a small amount of dimples with the carbides inside.
作者
沈漪
曹睿
闫英杰
车洪艳
秦巍
梁晨
SHEN Yi;CAO Rui;YAN Yingjie;CHE Hongyan;QIN Wei;LIANG Chen(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China;China Iron&Steel Research Institute Group,Beijing 10081,China;Advanced Technology&Material Co.,Ltd.,Beijing 10081,China;Engineering and Technology Research Center of Hot Isostatic Pressing,Zhuozhou 072750,China)
出处
《粉末冶金技术》
CAS
CSCD
北大核心
2023年第4期296-301,共6页
Powder Metallurgy Technology
基金
国家自然科学基金资助项目(52175325)。
关键词
粉末冶金刀具钢
显微组织
原位拉伸
断裂特征
powder metallurgy tool steels
microstructure
in-situ tensile
fracture characteristic
