Alloying behavior of W and Mo in the as-cast dual-phase FeNiCrAl multi-component alloys

The W and Mo are in the same groups of periodic table and are usually used as solid solution elements. In this investigation, the minor alloying behaviors of W and Mo in Fe₃₇Ni₃₆Al₁₇Cr₁₀ alloy were explored. The addition does not change the casting microstructure greatly, with dendrite region of FCC + B2 and inter-dendrite region of FCC phase. For tensile properties at ambient temperature, as-cast Fe₃₆Ni₃₆Al₁₇Cr₁₀Mo₁ alloy exhibited higher yield strength and fracture strength compared with Fe₃₇Ni₃₆Al₁₇Cr₁₀ alloy. Then, dual-phase alloys with Mo content of 2 and 3 at% were further designed and carefully studied. It is found that a nano-scale structure occurred in as-cast Fe₃₅Ni₃₆Al₁₇Cr₁₀Mo₂ alloy, where a large number of spherical BCC precipitates are distributed in the dendrite region of B2 phase. Meanwhile a mixture of irregular B2 phase and FCC phase is contributed to the inter-dendrite area. The Fe₃₅Ni₃₆Al₁₇Cr₁₀Mo₂ alloy exhibited the most excellent and comprehensive mechanical properties due to the fine structure and its high work hardening ability. The yield strength, ultimate tensile strength and fracture elongation of as-cast Fe₃₅Ni₃₆Al₁₇Cr₁₀Mo₂ alloy are 863 ± 20 MPa, 1285 ± 17 MPa and 16.0 ± 1.0 %, respectively, which is higher than the most of reported dual-phase as-cast FeNiCrAl multi-component alloys.