摘要:
本文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 wt.%）对WC-Cu-10Ni-5Mn-3Sn合金的微观结构及力学性能的影响。研究结果表明：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。出现的新相引起了WC晶粒尺寸的变化，进而造成了合金力学性能的变化。随着Cr3C2的添加量的增加，硬度和抗弯强度呈现先上升后下降的趋势，当Cr3C2添加量分别为0.4 wt.%和0.6 wt.%时，合金的硬度和抗弯强度达到了最大值，分别为93.1 HRA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 effect of small contents of Cr3C2 (0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 wt.%) dopant on the microstructure and mechanical properties of WC-Cu-10Ni-5Mn-3Sn alloy is investigated via pressureless melt infiltration tests at the temperature of 1210 ℃ and the infiltration time of 1.5 h. The results show that with the addition of Cr3C2, the amounts of Cr, W and C in solid solution in the binder alloy changes, and Ni2W4C and Cr7C3 appear successively in the binder alloy, and Cr7C3 readily absorbs W produced by the decomposition of WC to form (W,Cr)Cx and (Cr,W)C. The appearance or disappearance of the new phases leads to the changes in the grain size of the WC, which affects the mechanical properties of the alloy. The hardness and transverse rupture strength showed a trend of first increase and then decrease with the increase of Cr3C2 addition, and the hardness and transverse rupture strength reached the maximum value when the Cr3C2 addition was 0.4 wt.% and 0.6 wt.%, which were 93.1 HRA and 1720 MPa, respectively. The impact toughness decreases with increasing Cr3C2 addition and the best impact toughness value of 4.65 J·cm-2 was obtained for the alloy without Cr3C2 addition.
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