Transition Metal Alloying and Phase Stability in the Mo-Si-B System


The effect of transition metal substitution for Mo on the phase stability and multi-phase microstnictures in the Mo-Si-B ternary system has been examined. The metal-rich portion of the ternary Mo-Si-B system at equilibrium is comprised of thermally stable BCC Mo(ss) phase, a ternary-based Mo 5SiB2 (T2 phase), binary-based metal-rich silicides (Mo3Si [the A15 phase] and Mo5Si 3 [the T1 phase]) and borides (Mo2B and MoB phases). Systematic alloying with selected transition metals which are substitutional in both Mo(ss) and T2 phases such as Cr, V, Nb, W, Ti and Hf, has been performed to elucidate the roles of the substitution on the stability of the three phase fields of Mo(ss) + T2 + A15 and T2+ T1 + A15. The potential of the alloying effects on the microstructure design and control of the solidification pathways is further detailed.

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Conference Proceeding

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Journal Title

Materials Research Society Symposium - Proceedings