(北京有色金屬研究總院 粉末冶金及特種材料研究所， 北京 100088)
摘 要: 通過改進金相樣品的制備方法， 將納米晶WC-10Co硬質合金在場發(fā)射掃描電鏡10萬倍放大倍率下可獲得襯度良好、 WC晶粒輪廓清晰的二次電子像。 采用截距法定量測量了合金中WC晶粒尺寸， 結果表明： WC晶粒尺寸分布范圍為12~109 nm， 平均晶粒尺寸45 nm， 對應的三維WC平均晶粒度為70 nm。 根據合金中WC在低角度(2θ≤50°)的(001)WC， （100)WC和(101)WC晶面衍射峰數據， 用X射線衍射Scherrer公式測定的WC晶粒度的統(tǒng)計平均值為91 nm， 與定量金相分析結果接近并且都進入了納米尺度范疇。 實驗還比較了WC晶粒的統(tǒng)計數量和人為因素對評估數據的影響。
關鍵字: 硬質合金； 納米晶； 碳化鎢； 晶粒度
nanocrystalline WC-Co hardmetal
（ Powder Metallurgy and Special Materials Department,
General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract: Nanocrystalline WC-10Co hardmetal can be made by doping a new invented VC-based multi-grain-growth-inhibitor and suitable technical processing. The specification for quantitative measuring the grain size of WC in the alloy was explored. Under modified metallographic sample making and Murakami etching condition, the 100 000 multiple magnified second electron(SE) images with good contrast and clear profile of WC grain for the alloy can be obtained by FESEM. The linear interception (LI) method was used to quantitatively measure the interception of WC grain in the collected SE images. The results show that the distribution of WC grain size is 12-109 nm; the average interception of WC grains is 45 nm and the corresponding 3D mean grain size of WC is 70 nm. In another way, the grain size of WC was determined by XRD Scherer formulation for
(001)WC, （100)WC and (101)WC peaks at low brag angles(2θ≤50°). The calculated average value is 91 nm, which is agreeable with measured 3D grain size of WC and can be auribed to nano scale. The effects of counted grain numbers and human factor on the statistic data are also investigated and discussed.
Key words: hardmetals; nanocrystalline; WC; grain size
