W-Co-纳米碳管反应烧结制备高度取向硬质合金  

Preparation of cemented carbide having highly oriented WC grains by reactive sintering of W-Co-Nano carbon tubes

作　　者：裴燕斌[1] 果世驹[1] 孟飞[1] 杨霞[1] 

机构地区：[1]北京科技大学材料科学与工程学院粉末冶金研究所,北京100083

出　　处：《粉末冶金材料科学与工程》2005年第3期160-165,共6页Materials Science and Engineering of Powder Metallurgy

基　　金：国家863计划资助项目(2001AA337010)

摘　　要：研究了微米级钨粉(2μm)和多壁纳米碳管(直径10nm)反应烧结制备硬质合金的过程,制得了硬度高于HRA94的YG8硬质合金,其主要特点是WC晶粒(0001)晶面在垂直压制的方向上形成了高度的取向。对在800～1410℃不同反应温度下烧结的样品,进行了X射线衍射和扫描电镜分析,确定了钨和多壁纳米碳管的反应过程产物、不同晶面的取向程度和在不同温度下的显微组织形貌。研究表明,由于垂直方向的(0001)晶面的择优取向,这个方向上晶粒呈长条状和三角形,晶粒尺寸小于2μm,无明显的晶粒生长,与原料钨粉颗粒尺寸相比较,显示了颗粒尺寸的遗传性。新合金的硬度等力学性能高于传统工艺制备的相同钴成分、相同粘结相平均自由程的硬质合金。Reactive sintering of element powders is a novel route of producing YG cemented carbide, comparing with conventional liquid phase sintering. Thereby the new WC-Co base cemented carbides with highly oriented WC grains was prepared by reactive sintering of tungsten powder(2μm), cobalt powder(1.2μm) and nano carbon tubes(diameter: 10nm). The results show that the product, YG8 alloy with Co Content of 8% in mass fraction, has high hardness of HRA94; and the (0001)crystal planes of WC grain in the sintered alloy are highly oriented perpendicular to the direction of powder die-compaction. At various sintering temperatures from 800℃ to 1410℃, the reactive sintering stages, the orientation degree for some planes of WC, the morphologies of tungsten grains and nano carbon tubes are studied by XRD and SEM. Due to preferred orientation of (0001) crystal planes, triangular and strip-like grain with aspect ratio of 26 are observed and particulate size is smaller than 2μm, which is similar to the size of tungsten powder. Meanwhile, the alloy shows superior mechanical properties comparing to the conventional cemented carbides with the same Co content and the mean free path of binder phase.

关 键 词：硬质合金 反应烧结 纳米碳管 择优取向 

分 类 号：TF125.3[冶金工程—粉末冶金]