  The mechanical properties and microstructural evolution of a medium-entropy
alloy Co$_{17.5}$Cr$_{12.5}$Fe$_{55}$Ni$_{10}$Mo$_{5}$ (at%) in a low
temperature range (including the record low temperatures region down to 0.5 K)
were investigated. It has been established that low-temperature plastic
deformation initiates martensitic phase transformations in this alloy, and the
values of the dynamic modulus of elasticity correlate with the degree of phase
transformations.
