FeAlを結合相とする超硬合金のパルス通電焼結による作製

抄録

The microstructure, mechanical properties and high temperature oxidation resistance of WC-10mass%(Fe₆₅Al₃₅) and WC-10mass%(Fe_62.5A1_32.5B₅) alloys were investigated. Fe₆₅Al₃₅ or Fe_62.5A1_32.5B₅ were synthesized by mechanical alloying (MA) for 540 ks of Fe and AI powders, or Fe, Al and B powders. The obtained MA powders and WC powder were mixed with organic solvent in the planetary ball mill. The mixtures were consolidated by pulsed current sintering process.
WC-10mass%(Fe_62.5Al_32.5B₅) alloy has higher density and higher hardness than WC-10mass%(Fe₆₅Al₃₅) alloy. WC-10mass%(Fe_62.5Al_32.5B₅) alloy containing 0.37 mass% of oxygen has transverse-rupture strength of 0.78 GPa, which is higher than twice of that of alloys containing 3.4mass% of oxygen.
The oxidization of the cemented carbides with FeAl binder phase in the air starts at higher temperature than that of conventional WC-Co alloy. Especially, WC-10mass%(Fe_62.5Al_32.5B₅) alloy has excellent oxidization resistance at 1041 K.