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Cr3C2对WC‒Cu‒10Ni‒5Mn‒3Sn硬质合金微观结构及力学性能的影响

Effect of Cr3C2 on microstructure and mechanical properties of WC‒Cu‒10Ni‒5Mn‒3Sn cemented carbide

  • 摘要: 采用无压熔渗的方法,在熔渗温度为1210 ℃和熔渗时间为1.5 h的条件下,研究添加Cr3C2(0.0、0.2%、0.4%、0.6%、0.8%和1.0%,质量分数)对WC‒Cu‒10Ni‒5Mn‒3Sn硬质合金微观结构及力学性能的影响。结果表明:在熔渗过程中,WC发生部分分解,随着Cr3C2的添加,合金中出现Ni2W4C和Cr7C3,Cr7C3易吸收WC分解产生的W形成(W,Cr)Cx和(Cr,W)C。出现的新相引起WC晶粒尺寸的变化,进而改变了合金的力学性能。随着添加Cr3C2质量分数的增加,硬度和抗弯强度呈现先上升后下降的趋势,当Cr3C2质量分数分别为0.4%和0.6%时,合金的硬度和抗弯强度达到了最大值,分别为HRA 93.1和1720 MPa。添加Cr3C2不利于合金冲击韧性的提高,未添加Cr3C2的合金具有最高的冲击韧性(4.65 J·cm‒2)。

     

    Abstract: The WC‒Cu‒10Ni‒5Mn‒3Sn cemented carbide doped with Cr3C2 was prepared by pressureless melt infiltration at 1210 ℃ for 1.5 h, the effect of Cr3C2 dopant (0.0, 0.2%, 0.4%, 0.6%, 0.8%, and 1.0%, mass fraction) on the microstructure and mechanical properties of the WC‒Cu‒10Ni‒5Mn‒3Sn alloys was investigated. The results show that during the infiltration process, the WC particles partially decompose with the addition of Cr3C2, the Ni2W4C and Cr7C3 appear in the alloys, and the (W,Cr)Cx and (Cr,W)C are formed from Cr7C3 and W produced by the decomposition of WC. The emergence of new phases causes the change in WC grain size, thereby altering the mechanical properties of the alloys. With the mass fraction increase of Cr3C2, the hardness and flexural strength show the trend of first increasing and then decreasing. When the mass fraction of Cr3C2 is 0.4% and 0.6%, respectively, the hardness and flexural strength reach the maximum, which is HRA 93.1 and 1720 MPa, respectively. The addition of Cr3C2 is not conducive to the impact toughness, the alloys without Cr3C2 have the highest impact toughness as 4.65 J·cm‒2.

     

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