Austenite Formation in α-Phase Fe–Mn Alloy after Cold Plastic Working and Fast Heating by an Ar+ Ion Beam to 299°С

Resumo

The accelerated Ar⁺ ion irradiation at a fluence of 1.2 × 10¹⁵ cm^–2 for 4 seconds formed 6.2% austenite in a cold-worked Fe–6.29 at % Mn alloy with a structure of α ferrite. The related ion beam heating of a foil 25 μm thick is 299 ± 5°C, according to temperature monitoring. The content of manganese calculated from Mössbauer spectroscopy data in α and γ phases after irradiation is 5.5 and 17.1 at %, respectively. Grounds for the activation of low-temperature atomic mobility in the alloy are discussed in this paper. The mobility was shown to not be caused by the formation of radiation defects and radiation-enhanced diffusion. Nanoscale dynamic effects, resulting in the possible viscous flow of material at the front of post-cascade shock waves propagating in a undamped mode, play a vital role.