摘要
采用不同粒度的WC粉,加入VC、Cr3C2做抑制剂,制备WC-12%Co超细硬质合金。采用D60-25型钴磁仪测量合金磁饱和,利用排水法测定合金密度,采用三点弯曲法在CMT4504拉伸机上检测合金的抗弯强度,试样抛光后在JEOL-6701F扫描电镜下观察合金的显微组织。研究了不同的WC粉末粒度、球磨时间、烧结工艺对WC-12%Co的超细硬质合金性能的影响。结果表明:过压烧结可明显提高合金抗弯强度、硬度和密度;随着球磨时间的增加,合金硬度不断上升,抗弯强度先增后减;采用0.55μm粒度WC粉制备的合金的硬度明显高于0.70μm粒度WC粉制备的合金。在本次实验中,选用0.55μm的WC粉末原料,混合料球磨85 h,通过过压烧结,可制备出性能优良的WC-12%Co超细硬质合金,硬度HV≥1 800,抗弯强度≥3 400 N/mm2。
WC-12%Co ultrafine cemented carbides were preparated by WC powders with different particle size and adding VC and Cr3C2 as inhibitors.Magnetic saturations of the alloys were measured by D60-25-type cobalt magnetometer.Densities of the alloys were determined by drainage method.The three-point bending strength was tested on the CMT4504 tensile machine.Microstructures were observed by JEOL-6701F scanning electron microscope.The effects of original WC grain size,milling time and sintering process on properties of WC-12%Co ultrafine cemented carbide had been investigated.The results show that the pressure sintering can significantly improve the bending strength,hardness and density of the alloy.With the milling time increased,the hardness of the alloy increases and the bending strength increases firstly and then decreases.The alloy prepared from 0.55 μm WC powder has higher hardness.In this experiment,WC-12%Co ultrafine cemented carbide with excellent performance can be prepared by 0.55 μm WC powder,85 h milling time and pressure sintering.Its hardness of HV is not less than 1 800,and the flexural strength is not less than 3 400 N/mm2.
出处
《硬质合金》
CAS
2012年第3期141-145,共5页
Cemented Carbides
关键词
超细晶
硬质合金
抗弯强度
过压烧结
硬度
ultrafine grain
cemented carbide
flexural strength
pressure sintering
hardness
