粗WC颗粒对低钴硬质合金组织与性能的影响
发布时间：2018-08-23 15:28
【摘要】：以粒度为5μm的粗WC颗粒和粒度为1μm的细WC颗粒为原料,采用6种不同的粗/细颗粒质量配比,通过低压烧结制备Co含量(质量分数,下同)为7%的低钴WC Co硬质合金,测试材料的抗弯强度、断裂韧性和硬度,并采用扫描电镜(SEM)观察材料的微观组织、弯曲断口形貌及裂纹扩展情况,研究粗颗粒WC含量对低钴硬质合金组织与性能的影响。结果表明,随粗颗粒WC含量增加,WC晶粒度的分布表现为明显的双峰结构特征,从合金的弯曲断口观察到裂纹偏转以及穿晶断裂数量显著增加,以此阻碍裂纹扩展,从而提高合金的韧性。合金硬度随粗颗粒WC含量增加而下降。当粗颗粒含量(质量分数)为50%时,WC-7%Co硬质合金具有较好的综合力学性能,其硬度(HV30)为15.9 GPa,抗弯强度和断裂韧性分别为2 490 MPa和11.39 MPa·m1/2。
[Abstract]:Using coarse WC particles (5 渭 m) and fine WC particles (1 渭 m) as raw materials, low cobalt WC Co cemented carbides with 7% Co content (mass fraction below) were prepared by low pressure sintering with six different coarse / fine particle mass ratios. The flexural strength, fracture toughness and hardness of the materials were tested. The microstructure, bending fracture morphology and crack propagation were observed by scanning electron microscope (SEM). The effect of WC content of coarse particles on the microstructure and properties of low cobalt cemented carbides was studied. The results show that with the increase of WC content of coarse particles, the grain size distribution of WC exhibits obvious bimodal structural characteristics. The crack deflection and the number of transgranular fracture are observed from the bending fracture of the alloy, which hinders the crack propagation. Thus improving the toughness of the alloy. The hardness of the alloy decreases with the increase of WC content of coarse particles. When the content of coarse particles (mass fraction) is 50, WC-7 and Co cemented carbides have better comprehensive mechanical properties, their hardness (HV30) is 15.9GPa. the flexural strength and fracture toughness are 2 490 MPa and 11.39 MPa m ~ (1 / 2), respectively.
【作者单位】： 中南大学材料科学与工程学院;中南大学粉末冶金国家重点实验室;硬质合金国家重点实验室;
【基金】：国家自然科学基金资助(51371199) 中南大学研究生自主探索创新项目(502200569)
【分类号】：TG135.5
本文编号：2199486
[Abstract]:Using coarse WC particles (5 渭 m) and fine WC particles (1 渭 m) as raw materials, low cobalt WC Co cemented carbides with 7% Co content (mass fraction below) were prepared by low pressure sintering with six different coarse / fine particle mass ratios. The flexural strength, fracture toughness and hardness of the materials were tested. The microstructure, bending fracture morphology and crack propagation were observed by scanning electron microscope (SEM). The effect of WC content of coarse particles on the microstructure and properties of low cobalt cemented carbides was studied. The results show that with the increase of WC content of coarse particles, the grain size distribution of WC exhibits obvious bimodal structural characteristics. The crack deflection and the number of transgranular fracture are observed from the bending fracture of the alloy, which hinders the crack propagation. Thus improving the toughness of the alloy. The hardness of the alloy decreases with the increase of WC content of coarse particles. When the content of coarse particles (mass fraction) is 50, WC-7 and Co cemented carbides have better comprehensive mechanical properties, their hardness (HV30) is 15.9GPa. the flexural strength and fracture toughness are 2 490 MPa and 11.39 MPa m ~ (1 / 2), respectively.
【作者单位】： 中南大学材料科学与工程学院;中南大学粉末冶金国家重点实验室;硬质合金国家重点实验室;
【基金】：国家自然科学基金资助(51371199) 中南大学研究生自主探索创新项目(502200569)
【分类号】：TG135.5
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