超细碳化钨粉末团粒特性及其对硬质合金晶粒异常长大的影响  

Characteristics of Aggregate in Ultrafine Tungsten Carbide Powder and its Influence on Abnormal Grain Growth in Cemented Carbide

作　　者：陆必志[1,2] 

机构地区：[1]硬质合金国家重点实验室,湖南株洲412000 [2]株洲硬质合金集团有限公司,湖南株洲412000

出　　处：《硬质合金》2017年第4期233-242,共10页Cemented Carbides

基　　金："高档数控机床与基础制造装备"科技重大专项;精密工具创新能力平台建设(二期)(2015ZX04005008);子课题:原材料研究与粉末评价(2015ZX04005008-2)

摘　　要：选取两批超细钨粉,其中一批粒度分布均匀性较差,团粒较多;另一批粉末粒度分布均匀,团粒少。将两批钨粉在相同条件下进行碳化,制备成超细碳化钨,并分别配制成相同牌号的超细硬质合金,研究碳化钨团粒与钨粉团粒的关联性及碳化钨团粒对合金晶粒异常长大的影响。研究结果表明,碳化钨的团粒继承了钨粉团粒的基本特征,碳化过程会使团粒烧结致密化,钨粉、碳化钨粉团粒内部晶粒极细、结晶不完整、缺陷多。湿磨过程可以将碳化钨的团粒完全破碎分散,但是会生成大量活性高、结晶不完整、缺陷较为严重的纳米粒子,降低了粉末的均匀性。超细硬质合金晶粒异常长大与碳化钨的团粒有直接关系,碳化钨团粒中结晶不完整的碳化钨粒子是导致合金晶粒异常长大的主要原因。Two batches of ultrafine tungsten powder were selected, one batch had poor particle size distribution and more aggregate, and the other batch had uniform size distribution and less aggregate. Two batcches of ultrafine tungsten carbide powder were prepared by the carbonization of the two batches of tungsten powder under the same conditions, and then a certain type of ultrafine grained cemented carbide was prepared with the same process by using the two batches of tungsten carbide powder, respectively. The relevance between the aggregate in the tungsten powder and the tungsten carbide powder was investigated. The influence of the aggregate in the tungsten carbide powder on the abnormal grain growth in the cemented carbide was also researched. The results show that：（1） The basic characteristic of the aggregate in the tungsten carbide powder inherits that in the tungsten powder. The carbonization process results in the densification of the aggregate. The grains in the aggregate in the tungsten powder and the tungsten carbide powder is very fine, the crystallization is incomplete, and more defects appear.（2） The wet milling process can completely break up the aggregate in the tungsten carbide powder, but a large amount of nano-size grains with high activity, incomplete crystallization and serious defects will be produced, thus the uniformity of the tungsten carbide powder is reduced.（3） The abnormal grain growth in the ultrafine grained cemented carbide is directly related to the aggregate in the tungsten carbide powder, that is the grains with incomplete crystallization in the tungsten carbide aggregate leads to the formation of the abnormal grain growth.

关 键 词：超细碳化钨 团粒 均匀性 结晶完整性 异常长大 

分 类 号：TG135.5[一般工业技术—材料科学与工程]