烧结温度对纳米WC-6Co复合粉烧结的影响
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摘要
研究了不同烧结温度对纳米WC-6Co复合粉烧结的影响.采用CSS-44100型万能材料实验机进行抗弯强度测试.材料的硬度通过HR-150A型洛氏硬度仪测量.分别在S-3400N型扫描电镜的背散射电子和二次电子模式下观察试样的显微组织形貌和断口形貌.结果表明:当烧结温度在1460℃时,晶粒分布均匀,材料的孔隙率最低.随烧结温度的升高,材料的抗弯强度和硬度先增加后降低.当在1460℃烧结时,较低的孔隙率和显微组织分布均匀导致材料有较高的抗弯强度.随烧结温度的继续增加,晶粒聚集长大现象严重,孔隙率增加,导致材料的抗弯强度大幅降低.当烧结温度在1460℃时,材料有较高的硬度和断裂韧性.
The effect of sintering temperature on the sintering of nano WC-6Co powder was studied.The transverse rupture strength(TRS) of the cemented carbide was tested by CSS-44100 universal material machine. The hardness(HRA) was measured by HR-150 A Rockwell hardness tester. The microstructures and fracture surface morphology were observed by S-3400 N scanning electron microscopy(SEM) in backscattered electron(BSE) mode and secondary electron(SE) mode, respectively. The results showed that when the sintering temperature was 1460℃, the grain was distributed uniformly, and the porosity was the lowest. The TRS increased firstly and then decreased with increasing of sintering temperature. The TRS was the highest sintering in 1460℃, which was resulting from the smallest porosity and homogeneous microstructure. As the sintering temperature continued to increase, the aggregation of the grain occurred, and the porosity increased, which resulted in decreasing of TRS. The hardness and fracture toughness(K1C) of the cemented carbide was higher sintering in 1460℃.
The effect of sintering temperature on the sintering of nano WC-6Co powder was studied.The transverse rupture strength(TRS) of the cemented carbide was tested by CSS-44100 universal material machine. The hardness(HRA) was measured by HR-150 A Rockwell hardness tester. The microstructures and fracture surface morphology were observed by S-3400 N scanning electron microscopy(SEM) in backscattered electron(BSE) mode and secondary electron(SE) mode, respectively. The results showed that when the sintering temperature was 1460℃, the grain was distributed uniformly, and the porosity was the lowest. The TRS increased firstly and then decreased with increasing of sintering temperature. The TRS was the highest sintering in 1460℃, which was resulting from the smallest porosity and homogeneous microstructure. As the sintering temperature continued to increase, the aggregation of the grain occurred, and the porosity increased, which resulted in decreasing of TRS. The hardness and fracture toughness(K1C) of the cemented carbide was higher sintering in 1460℃.
引文
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[3]Fan P,Fang Z Z,Guo J.A review of liquid phase migration and methods for fabrication of functionally graded cemented tungsten carbide[J].International Journal of Refractory Metals and Hard Materials,2013,36(1):2-9.
[4]尚自河,李安海,赵军,等.超细晶粒硬质合金刀具材料的研究进展[J].工具技术,2015(2):3-8.
[5]Shao G Q,Duan X L,Xie J R,et al.Sintering of nanocrystalline WC-Co composite powder[J].Reviews on Advanced Materials Science,2003,5(4):281-286.
[6]Kim H C,Shon I J,Yoon J K,et al.Consolidation of ultrafine WC and WC-Co hard materials by pulsed current activated sintering and its mechanical properties[J].International Journal of Refractory Metals&Hard Materials,2007,25(1):46-52.
[7]Kim H C,Shon I J,Yoon J K,et al.One step synthesis and densification of ultra-fine WC by high-frequency induction combustion[J].International Journal of Refractory Metals&Hard Materials,2006,24(3):202-209.
[8]Kim H C,Yoon J K,Doh J M,et al.Rapid sintering process and mechanical properties of binderless ultra fine tungsten carbide[J].Materials Science and Engineering:A,2006(435/436):717-724.
[9]Shetty D,Wright I,Mincer P,et al.Indentation fracture of WC-Co cermets[J].Journal of Materials Science,1985(20):1873-1882.
[10]Shubert W D,Bock A,Lux B.General aspects and limits of conventional ultrafine WC powder manufacture and hard metal production[J].International Journal of Refractory Metals&Hard Matcria1s,1995,13(5):281-296.
[11]关振铎,张中太.无机材料物理性能[M].北京:清华大学出版社,2001.