Effects of Mo/B Atomic Ratio on the Properties and Structure of Chromium Adding Iron-Molybdenum Complex Boride Base Hard Alloys

Abstract

The effects of Mo/B atomic ratio on the mechanical properties and the phase formation in Fe-5B-5Cr-xMo alloys were studied. The effects on alloy partitioning, lattice parameters and the morphology of Mo2FeB2 type complex boride in the alloys were also studied.
The transverse rupture strength (TRS) and hardness of the iron-molybdenum complex boride base hard alloys depend strongly on their Mo/B atomic ratio (Mo content), the type of ferrous binder and the morphology of the Mo₂FeB₂ type complex boride. The best combination of TRS and hardness is obtained at an optimal Mo/B atomic ratio of 1.0 where very little third phase exists such as M₆C (M: metal) other than Mo₂FeB₂ type complex boride and a martensitic binder, and the small grain size boride phase are also present.