Fe-25at%Alを結合相とした超硬合金の作製

抄録

The microstructure and mechanical properties of WC-10mass%(Fe-25at%Al), WC-10mass%(Fe-22.5at%Al-5at%B) and WC-20mass%(Fe-25at%Al) alloys were investigated. Fe-25at%Al and Fe-22.5at%Al-5at%B were synthesized by mechanical alloying (MA) for 540 ks of Fe and Al powders, and Fe, Al and B powders, respectively. The obtained MA powders and WC powder were mixed under the wet condition or the dry condition. For the mixing under the wet condition, the attrition ball milling with the organic solvent was used. For the mixing under the dry condition, the planetary ball milling in Ar gas atmosphere was used. The mixtures were consolidated by a pulsed current sintering (PCS) process.
The density and hardness of WC-10mass%(Fe-22.5at%Al-5at%B) alloy prepared by the wet mixing were higher than these of WC-10mass%(Fe-25at%Al) alloy. However, these alloys showed low traverse-rupture strength (TRS) value of 1 GPa because of high oxygen content. WC-10mass%(Fe-25at%Al) alloy prepared by the dry mixing became more homogeneous and higher density with increasing the mixing time. The hardness of WC-10mass%(Fe-25at%Al) mixed for 72ks was more than 93 HRA. WC-20mass%(Fe-25at%Al) alloy prepared by the dry mixing showed almost theoretical density, and thus showed hardness of 90.5 HRA and TRS of 1.3 GPa.