WC-Co类硬质合金的低周冲击疲劳性能研究  

Study on Low Cycle Impact Fatigue Performance of WC-Co Cemented Carbides

作　　者：陈鼎[1] 姚亮[1] 陈振华[1] 王辉平[2,3] 彭文[2,3] 

机构地区：[1]湖南大学材料科学与工程学院,湖南长沙410082 [2]株洲硬质合金集团有限公司,湖南株洲412000 [3]硬质合金国家重点实验室,湖南株洲412000

出　　处：《稀有金属与硬质合金》2017年第3期71-75,80,共6页Rare Metals and Cemented Carbides

基　　金：硬质合金国家重点实验室项目(201403001)

摘　　要：为研究WC-Co类硬质合金的冲击疲劳断裂机制和微观组织参数对其低周冲击疲劳性能的影响,对6种牌号不同WC晶粒尺寸及Co含量的硬质合金进行了冲击疲劳试验,并用扫描电子显微镜(SEM)观察冲击疲劳断口。结果表明:当硬质合金承受冲击加载时,裂纹从粉末冶金缺陷处萌生,萌生的裂纹与孔洞相互连接形成主裂纹,主裂纹快速扩展导致材料疲劳失效。Co含量越高的硬质合金其疲劳敏感性越强,冲击疲劳寿命越短;WC晶粒尺寸越大的硬质合金其冲击疲劳寿命越长。To study impact fatigue fracture mechanism of WC-Co cemented carbides and effects of microstructure parameters on their low cycle impact fatigue performance, impact fatigue tests were carried out for six kinds of cemented carbides with different WC grain size and Co content. And the impact fatigue fracture was observed by scanning electron microscopy. The results show that the cracks in the cemented carbides with impact loading are initiated from the powder metallurgy defects, the initiated cracks are interconnected with the holes to form the main cracks, and the rapid propagation of the main cracks leads to fatigue and failure of cemented carbides. The cemented carbide with higher Co content has greater fatigue sensitivity and shorter impact fatigue lifetime. The cemented carbide with larger WC grain size has longer impact fatigue life.

关 键 词：硬质合金 WC-CO 冲击疲劳 断裂机制 WC晶粒尺寸 CO含量 

分 类 号：TG135.5[一般工业技术—材料科学与工程]