Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第30卷    第8期    总第257期    2020年8月

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文章编号:1004-0609(2020)-08-1828-09
微波反应烧结制备WC-Co硬质合金工艺性能
鲍 瑞1,郭圣达2,易健宏1,陈 颢2,羊建高2,余 飞2

(1. 昆明理工大学 材料科学与工程学院,昆明 650093;
2. 江西理工大学 工程研究院,赣州 341000
)

摘 要: 以W粉、Co粉和碳黑为原料,通过球磨、压制成形及微波反应烧结制备WC-6Co硬质合金。采用XRD、SEM、密度计和维氏硬度计等研究微波反应烧结温度、升温速率、保温时间和W粉粒度4个因素对硬质合金组织与性能的影响。结果表明:选用粒度为1.3 μm的W粉为原料,当温度大于1100 ℃时,W即可被C完全碳化生成WC;当温度为1300 ℃时合金致密性较好,维氏硬度(HV30)与断裂韧性(Wk)分别为1999 N/mm2和8.51 MPa/m1/2,继续提高温度至1400 ℃时合金性能无明显变化。烧结温度越低、升温速率越大、保温时间越短,合金残留孔隙越多,导致维氏硬度与断裂韧性性能下降。当微波反应烧结温度为1300 ℃、升温速率100 ℃/min和保温时间10 min时制备的WC-6Co硬质合金微观组织均匀和综合性能最佳。选用粒度为27.0 μm的W粉为原料按照最佳工艺烧结制备出WC-6Co硬质合金,并与平均粒度1.3 μm的W粉制备的合金进行对比发现粗W粉颗粒制备的合金中存在W2C,微波反应烧结工艺参数与W粉平均粒度相关。

 

关键词: 微波反应烧结;硬质合金;微观组织;性能;烧结参数

Microwave reaction sintering on WC-Co cemented carbides fabrication
BAO Rui1, GUO Sheng-da2, YI Jian-hong1, CHEN Hao2, YANG Jian-gao2, YU Fei2

1. School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China;
2. Project Research Institute, Jiangxi University of Science and Technology, Ganzhou 341000, China

Abstract:Tungsten powder, cobalt powder and carbon black were invoked as raw materials.WC-6Co cemented carbides were prepared by ball-milling, compression moulding and microwave reaction sintering. The effects of sintering factors (Sintering temperature, heating rate and holding time) and the average particle size of W powders on the microstructure and properties of cemented carbides were investigated by XRD, SEM, Vickers hardness tester, et al. The results show that W powders with an average size of 1.3 μm can be carbonized to WC by C when the temperature is greater than 1100 ℃. The high densification of cemented carbide can be achieved when the temperature is 1300 ℃. The Vickers hardness (HV30) and fracture toughness (Wk) are 1999 N/mm2 and 8.51 MPa?m1/2, respectively. No obvious property changes occur when sintering temperature increases to 1400 ℃. The residual pores in the alloy increase with reducing the sintering temperature, increasing the heating rate and reducing the holding time, which would result in the decrease of HV30 and Wk. It is considered that the microstructure is uniform and the comprehensive properties is the best when the microwave reaction sintering temperature is 1300 ℃, the heating rate is 100 ℃/min, and the holding time is 10 min. Subsequently, coarse grained WC-6Co cemented carbides are prepared from W powders with an average size of 27.0 μm and compared with fine grained WC-6Co cemented carbides. The results show that W2C exists in the alloy prepared from coarse W powders. The parameters of microwave reaction sintering are also affected by the average size of W powders.

 

Key words: microwave reaction sintering; cemented carbides; microstructure; properties; sintering parameters

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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