热处理对钢结硬质合金TLMW50中复式碳化物形态与分布的影响

利用SEM对烧结态和热处理态钢结硬质合金TWLM50微观组织中复式碳化物形态与分布进行研究。结果表明：烧结态钢结硬质合金TLMW50微观组织中主要复式碳化物Fe3W3C、Fe2W2C相形状基本呈现长条状，宽约10—20μm之间，颗粒长度可达10～60μm之间，且复式碳化物的晶粒上还有细小的三角状二次碳化物析出。经过1050℃淬火，250℃回火复式碳化物颗粒的棱角有所钝化，条形颗粒明显减少。二次碳化物析出数量明显减少，大部分二次碳化物溶于或与初生复式碳化物发生反应，形成复式碳化物，且随机分布在初生复式碳化物上。热处理导致钢结硬质合金TWLM50硬度提高到65HRC，耐磨性显著提高。

Effect of Heat Treatment on the Distribution and Shape of Multiple Carbides in Steel-bonded Cemented Carbide TLMW50

The distribution and the shape of multiple carbides in sintered and heat treated steel- bonded cemented carbide TLMW50 were investigated by SEM. The results showed that shape of multiple carbides including Fe3W3C and Fe2W2C was rectangular. The sizes were 10 - 20 μm in width and 10 ～ 60μm in length. Moreover, the secondary carbide with the triangle shape was observed in multiple carbides. The edge angle of multiple carbides was inactive,and the ratio of rectangular carbides was decreased by heat- treatment including quenched at 1 050 ℃ followed by tempering at 250℃. The amount of secondary carbide was decreased and evolved into multiple carbides with a random distribution because of the dissolution and reaction between them. The rigidity of steel- bonded cemented carbide TLMW50 was increased to 65HRC by the heat - treatment process. The wear resistance of TLMW50 was significantly improved.