摘要
以W粉、Co粉及炭黑为原料制备η相粉末,向WC–10Co混合粉末中加入质量分数为8%的η相粉末和一定化学计量比的工业炭黑,利用传统粉末冶金工艺制备含板状WC晶粒的硬质合金。研究了合成温度对η相的影响以及烧结温度、固相烧结升温速率对板状WC晶粒的作用。结果表明:在氮气保护气氛下,当行星球磨时间为12 h时,1050℃保温1 h即可得到Co_6W_6C相含量较高的η相粉末。在保温时间为1 h的前提下,烧结温度为1440℃,有利于合金中板状WC晶粒的生长,此时合金的力学性能最佳;在烧结温度与保温时间一定的前提下,当固相升温速率由6℃/min降低到2℃/min时,板状WC晶粒的尺寸和长厚比逐渐增加,合金的强度保持不变,维氏硬度提高了3%,断裂韧性提高了13%。
The η phase powder was prepared by using Co powder,W powder,and carbon black as the raw materials.The WC–Co cemented carbide with plate-like WC grains was prepared by the traditional powder metallurgy process through adding 8wt% η phase powder and the industrial carbon black in stoichiometric ratio to the ball-milled WC–10Co batch.The effect of synthesis temperature on the preparation of η phase and the influence of sintering temperature and heating rate on the plate-like WC grains during the solid state sintering were investigated.The results indicate that,in the protective atmosphere of nitrogen,the η phase powder with high content of Co6W6C can be prepared at the synthesis temperature of 1050 ℃（holding for 1 h） after planetary milling for 12 h.Sintering at 1440 ℃ and holding for 1 h are advantageous for the growth of plate-like WC grains,and the mechanical properties of alloy are optimal.When the sintering temperature and holding time are constant,the size and length/thickness ratio of plate-like WC grains increase gradually with the decrease of heating rate from 6 ℃/min to 2 ℃/min during the solid state sintering;meanwhile,the Vickers hardness and fracture toughness of alloy are increased by 3% and 13%,respectively,but the transverse rupture strength has no change.
出处
《粉末冶金技术》
CAS
CSCD
北大核心
2017年第1期39-45,共7页
Powder Metallurgy Technology
关键词
硬质合金
烧结工艺
碳化钨
晶粒
cemented carbide
sintering process
tungsten carbide
grains
