Slip and Twinning in the [49]-Oriented Single Crystals of a High-Entropy Alloy

Using [49] - oriented single crystals of an FCC Fe20Ni20Mn20Cr20Co20 (at.%) high-entropy alloy subjected to tensile deformation, the temperature dependence of critical resolved shear stresses tau(cr)(T) and the deformation mechanism of slip and twinning are investigated in the early stages of deformation at epsilon ae<currency> 5% within the temperature interval T = 77-573 K. It is shown that tau(cr) increases with decreasing the testing temperature and the tau(cr)(T) temperature dependence is controlled by the slip of perfect dislocations a/2 < 110 >. The early deformation stages epsilon ae<currency> 5% are associated with the development of planar slip by pileups of perfect dislocations a/2 < 110 >, stacking faults and mechanical twins, which is observed in the temperature interval from 77 to 423 K. A comparison of the temperature dependence tau(cr)(T) and the development of mechanical twinning is performed between the [49] -oriented single crystals of the Fe20Ni20Mn20Cr20Co20 high-entropy alloy, the single crystals of the austenitic stainless steel, Fe - 18% Cr - 12% Ni - 2Mo (wt.%) without nitrogen atoms (Steel 316) and Hadfield steel, Fe - 13% Mn - (1-1.3)% C (wt.%).