【摘要】 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。更多还原

【Abstract】 WC-6 Co ultrafine cemented carbides were prepared at different sintering temperature and using the mixtures with different total carbon content(6.11%,6.13%,6.15%,6.17%,6.19%,6.21%,6.23%and 6.25%).The magnetic properties and microstructure of the samples were analyzed,and the effects were studied of carbon content on WC grain growth activation energy of WC-6 Co cemented carbides.The results show that with the increase of total carbon content,cobalt magnetism(Com)of the alloy sample is also gradually increased.For WC-6 Co sintered at different temperature,corecive force(Hc)firstly increases and then decreases,and WC grain size decreases at first and then increases with the increase of Com.When the Com value is about 5%,Hcreaches the maximum and WC grain size reaches the minimum.WC grain growth activation energy firstly increases and then decreases with Com increasing,and reaches the maximum when Com is about 5.2%.With the increase of carbon content in a low range,more(Cr_x,V_y)Czcarbide(agrain growth inhibitor)is generated on the WC grain surface.But with the further increase of carbon content,the production amount of(Cr_x,V_y)Czcarbide has reached the extreme value,while the temperature for generating liquid phase further declines and liquid volume dramatically increases,resulting in decreased WC grain growth activation energy.更多还原