Novel Fe36Mn21Cr18Ni15Al10 high entropy alloy with bcc/B2 dual-phase structure

A novel Fe36Mn21Cr18Ni15Al10 high entropy alloy composed mostly of inexpensive components was produced by vacuum arc melting. In the as-cast condition the alloy had a dual-phase structure consisted of a bcc matrix and homogeneously distributed in the matrix cuboidal B2 ordered particles. The matrix phase was enriched with Fe and Cr, and B2 particles were composed mostly of Ni and Al. The alloy had high compression yield strength of 940-990 MPa at temperatures up to 400 degrees C. Further increase in temperature resulted in pronounced softening. The alloy could be compressed to 50% reduction without fracture at room temperature, but had a limited tensile ductility, especially at room temperature - elongation to fracture was only 2.5%. Annealing at 1200 degrees C did not change the structure of the alloy noticeably, but after annealing at 1000 degrees C an additional fcc phase appeared. The formation of the fcc phase caused pronounced softening. The comparison of the experimental results on the phase composition of the alloy with CALPHAD predictions showed reasonable agreement. Possibilities to increase stability of dual bcc-B2 structure were discussed. (C) 2017 Elsevier B. V. All rights reserved.