| 梯度结构硬质合金的疲劳断裂 |
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| 引用本文： | 李亚林,刘咏,周永贵,李昆,赵中伟. 梯度结构硬质合金的疲劳断裂[J]. 粉末冶金材料科学与工程, 2011, 16(5): 747-754 |
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| 作者姓名： | 李亚林 刘咏 周永贵 李昆 赵中伟 |
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| 作者单位： | 1. 中南大学粉末冶金国家重点实验室,长沙,410083
2. 中南大学粉末冶金国家重点实验室,长沙410083;自贡硬质合金有限责任公司,自贡,643011 |
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| 基金项目： | 湖南有色研究基金资助项目(Y2008-01-001) |
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| 摘 要： | 采用三点抗弯的方法研究WC-6Co梯度结构硬质合金和均质WC-6Co硬质合金的疲劳行为,探讨疲劳断口形貌与破坏机制的关系。结果表明:梯度结构硬质合金的疲劳裂纹在亚表面萌生;梯度结构硬质合金表层Co相发生明显塑性变形,WC相以沿晶断裂为主;中间层Co相变形也很明显,WC相解理断裂增加;内层Co相塑性变形很少,WC、η相以解理断裂为主;均质硬质合金Co相塑性变形明显,WC以沿晶、解理断裂为主,各部位断口形貌接近;梯度结构硬质合金的疲劳极限比均质硬质合金高约100 MPa;梯度结构硬质合金中疲劳裂纹沿垂直于试样下表面、平行于Co相梯度的方向形核,而均质硬质合金的疲劳裂纹沿平行于试样外表面方向形核。在应力集中效应、循环应力的作用下,Co相的马氏体相变是裂纹在亚表面萌生的主要原因;马氏体相变使Co相成为裂纹形核的快速通道,裂纹沿Co相梯度方向形核。
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| 关 键 词： | 梯度结构硬质合金 疲劳断裂 疲劳裂纹形核 |
Fatigue fracture of functionally-graded cemented carbides |
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| LI Ya-lin,LIU Yong,ZHOU Yong-gui,LI Kun,ZHAO Zhong-wei. Fatigue fracture of functionally-graded cemented carbides[J]. materials science and engineering of powder metallurgy, 2011, 16(5): 747-754 |
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| Authors: | LI Ya-lin LIU Yong ZHOU Yong-gui LI Kun ZHAO Zhong-wei |
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| Affiliation: | LI Ya-lin1,LIU Yong1,ZHOU Yong-gui1,2,LI Kun1,ZHAO Zhong-wei1 (1.State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China,2.Zigong Cemented Carbide Corp Ltd,Zigong 643011,China) |
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| Abstract: | Three-point-bending fatigue tests were conducted on both WC-6(mass fraction,the same below)% Co functionally-graded cemented carbides(FGCCs) and conventional WC-6%Co cemented carbides.The relationship between fatigue fracture morphology and failure mechanism were investigated.The results show that the fatigue cracks are nucleated in the subsurface area of both FGCCs and conventional cemented carbides;obvious plastic deformation of Co-phase and intergranular fracture of WC-phase are observed at the surface l... |
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| Keywords: | functionally-graded cemented carbides fatigue fracture fatigue-crack nucleation |
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