Investigation of the Structure and Properties of the Fe-Ni-Co-Cu-V Multiprincipal Element Alloys

The effect of V addition to the Fe-Ni-Co-Cu system was analyzed in the present work. Three distinct alloys were prepared in a vacuum electric arc furnace in an argon atmosphere and later cast into a copper mold. Investigation of the structure of alloys was performed by scanning electron microscopy (SEM) and by X-ray diffraction. The mechanical properties were also tested in compression. The phase diagrams of the Fe-Ni-Co-Cu-V system were thermodynamically calculated and the results are compared with those of differential scanning calorimetry and the results of SEM observation. It is shown that as a result of crystallization, two solid solutions with FCC crystal structures are formed. The addition of equiatomic amount of vanadium to Fe-Ni-Co-Cu system alloys facilitates phase separation in the liquid state. The addition of V causes an increase in the yield strength by solid solution hardening by about 30 pct and maximum true stress by 40 pct, yet retaining good plasticity. It also does not cause formation of an intermetallic compound.