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超细WC粉末是制备超细硬质合金的主要原材料,本文采用XRD﹑SEM﹑TEM等分析手段,研究了三种不同粒度的超细WC粉末中微观缺陷的种类及其在晶粒中的分布,探讨了超细WC粉末微观缺陷的形成原因。分析结果表明:超细WC粉末主要为多晶颗粒,其位错密度较大,高于常态下一般的金属或合金。其微观缺陷的存在形式主要有位错﹑层错﹑孪晶等。在钨转化为碳化钨的相变过程中,钨原子密度由6.309 446个/nm3降低为3.211 922个/nm3,体积膨胀31%,为了释放其中的应力,必须存在有数量较多的缺陷。
Ultrafine WC powder is the main raw material for the preparation of ultrafine cemented carbide. In this paper, the XRD, SEM, TEM and other analytical tools were used to study the microscopic defects in three different sizes of ultrafine WC powder and its distribution in the grains , Discussed the formation of microscopic defects of ultrafine WC powder. The results show that the ultrafine WC powder mainly consists of polycrystalline particles with a higher density of dislocations than the normal metal or alloy. The existence of micro-defects in the form of mainly dislocation ﹑ ﹑ twin and so on. During the transformation of tungsten into tungsten carbide, the density of tungsten atoms decreased from 6.309 446 / nm3 to 3.211 922 / nm3, and the volume was expanded by 31%. To release the stress, there were a large number of defects.