XCQ16和20Mn2车轴用钢疲劳失效的微观机理 |
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作者姓名: | 黄重国 董红磊 袁清华 井溢农 任学平 |
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作者单位: | 北京科技大学土木与环境工程学院,北京,100083;包头钢铁(集团)公司技术中心,包头,014010;北京科技大学材料科学与工程学院,北京,100083 |
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摘 要: | 利用扫描电镜(SEM)对XCQ16和20Mn2两种车轴用钢疲劳断口和裂纹扩展断口进行分析,研究疲劳失效过程中的裂纹萌生及扩展机理.结果表明:裂纹均是从试样表面萌生,非金属夹杂和位错是主要的萌生机制;XCQ16钢在疲劳断口中部区的裂纹闭合效应大于20Mn2钢,裂纹扩展较慢;两者在裂纹扩展区的扩展机理不同,XCQ16钢属于塑性断裂,20Mn2钢属于解理断裂;在非金属夹杂上,XCQ16钢多含氧化物和硫化物的混合夹杂,20Mn2钢主要是氧化物夹杂,混合夹杂对材料的疲劳性能影响较小.
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关 键 词: | 疲劳失效 断口分析 疲劳裂纹萌生 疲劳裂纹扩展 微观机理 非金属夹杂物 |
收稿时间: | 2008-10-22 |
Microscopic mechanism of XCQ16 and 20Mn2 axle steel fatigue failure |
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Authors: | HUANG Zhong-guo DONG Hong-lei YUAN Qing-hua JING Yi-nong REN Xue-ping |
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Abstract: | The fatigue fracture and crack propagation of XCQ16 and 20Mn2 axle steel were observed by SEM. Based on the observed results, the mechanisms of fatigue crack initiation and propagation were studied. It is shown that cracks initiate from the sample surfaces. The main mechanism of crack initiation is non-metallic inclusions and dislocations. The crack closure effect of XCQ16 steel is stronger than 20Mn2 steel in crack propagation areas, leading to a lower crack growth rate. The fracture mechanisms of the two steels are different:plastic fracture for XCQ16 and cleavage fracture for 20Mn2. Non-metallic inclusions in XCQ16 are composed of oxide inclusions and sulfide inclusions, but mainly oxide inclusions in 20Mn2 steel. The mixed inclusions in XCQ16 steel have less effect on its fatigue property. |
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Keywords: | fatigue failure fracture analysis fatigue crack initiation fatigue crack propagation microscopic mechanism non-metallic inclusions |
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