1406 固相反応によるWC超硬合金の合成(S09-2 粉末成形とその評価II,21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

抄録

The synthesis of WC-Co alloy from elemental powders was investigated. Especially the the forming WC phase during the solid-phase sintering was discussed. The chemical composition of WC-Co alloy was chosen to be WC-20vol%Co. The powder mixture of stoichiometric quantities of elemental powders was mechanical alloyed by using lowenergy ball mill under an Ar atmosphere. After 1800ks milling, the X-ray diffraction profile showed only elemental W phase. At DTA runs, W_2C and Co_6W_6C phase formed about 1140K and then transformed to WC and W_3Co_3C with increasing temperature. Therefore, it is considered that the WC phase synthesized at the sintering process, not milling stage like other investigations using high energy ball mill. 1800ks milled powder was consolidated by using pulse current sintering method at the temperature of 1373K. The compact consisted mainly of WC with Co with small amount of W_3Co_3C. The hardness of the compact was HV1648 and HRA91.8. The 3-point bending strength was about 2GPa.