Atomistic investigation of elementary dislocation properties influencing mechanical behaviour of Cr15Fe46Mn17Ni22 alloy and Cr20Fe70Ni10 alloy

•The elementary dislocation properties in a model alloy of austenitic stainless steel (Cr20Fe70Ni10) and a model alloy of high entropy alloy (Cr15Fe46Mn17Ni22) have been investigated.•There is a strong fluctuation of the local stacking fault energy (SFE) in both alloys with Cr15Fe46Mn17Ni22 alloy having a larger fluctuation.•This implies that critical stress for the dislocation motion of the ½〈110〉{111} edge dislocation is larger in the Cr15Fe46Mn17Ni22 alloy in comparison with the Cr20Fe70Ni10 alloy.•This indicates that the mechanical behaviour in Cr15Fe46Mn17Ni22 alloy will be high in comparison with the Cr20Fe70Ni10 alloy.•The proposed constitutive equation accurately predict the dislocation velocity over three orders of magnitudes in the Cr20Fe70Ni10 and Cr15Fe46Mn17Ni22 alloys.