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配制8组不同总碳含量(6.11%、6.13%、6.15%、6.17%、6.19%、6.21%、6.23%、6.25%)的WC-6Co混合料,在不同烧结温度下烧结制备WC-6Co超细晶硬质合金试样,并检测试样的磁学性能和微观结构,研究了碳含量对WC-6Co超细晶硬质合金WC晶粒长大激活能的影响。结果表明:随着混合料总碳含量的提高,硬质合金试样的Com值也逐步增加;在不同的烧结温度下,随着Com值的增加,Hc值均先升高后降低,硬质合金WC晶粒尺寸先减小后增大,且均在Com值约为5%时Hc达到最大值、WC晶粒尺寸达到最小值;WC晶粒长大激活能随Com值的增加先上升后下降,在Com为5.2%左右时达到最高值。这是由于碳含量较低时,随着碳含量的增加,WC晶粒表面生成的晶粒长大抑制剂(Cr_x,V_y)Cz碳化物增加,但随着碳含量的继续增加,(Cr_x,V_y)Cz的生成量已达到极值,而产生液相的温度进一步下降,液相量急剧增加,WC晶粒长大激活能又开始下降。
WC-6Co mixture with different total carbon content (8.11%, 6.13%, 6.15%, 6.17%, 6.19%, 6.21%, 6.23%, 6.25%) was prepared and sintered at different sintering temperatures The effects of carbon content on WC grain growth activation energy of WC-6Co ultrafine-grained cemented carbide WC were investigated. The results show that with the increase of the total carbon content, the Com value of the cemented carbide samples increases gradually. At different sintering temperatures, the values of Hc increase first and then decrease with the increase of Com value, The grain size of the alloy WC first decreases and then increases, and reaches the maximum when the Com value is about 5%, and the WC grain size reaches the minimum value. The activation energy of WC grain growth first increases with Com value Decline, reaching the highest when Com is around 5.2%. This is due to the fact that with the increase of carbon content, the grain growth inhibitor (Cr_x, V_y) Cz carbides produced on the surface of WC grains increases with the increase of carbon content. However, with the increase of carbon content (Cr_x, V_y) Cz has reached the extreme value, and the temperature of the liquid phase decreases further, the liquid phase increases sharply, WC grain growth activation energy begins to decline again.