Mössbauer study of the polymorphism in iron and iron-nickel alloys under deformation and high pressure
Structural and phase transitions in iron and binary iron-nickel alloys containing 6–32 at % nickel have been investigated by Mössbauer spectroscopy in situ under quasi-hydrostatic compression and compression shear. It is shown that the deformation decreases the onset pressure of the α-phase transition to the high-pressure ∈ and γ phases. Shear changes the transformation mechanism due to the formation of a large number of structural defects; it is an independent parameter of the phase transition kinetics. Compression shear leads to an irregular change in the hyperfine parameters of the initial and newly formed phases, which is due to the stress relaxation as in the trip effect.