Residual stresses in electron-beam coatings with a nitrogen-austenite matrix and structural mechanisms of their relaxation

The structure, distribution of elastic microdeformations related to the effect of residual stresses of the 1st and 2nd kind in nitrogen austenite coatings prepared by electron-beam overlaying and the mechanisms of relaxation of residual stresses in the substrate-coating system have been investigated. The state of stress is characterized by a change in sense over the coating thickness. An analysis of experimental data shows that the relaxation of residual stresses results in the formation of a structure with an enhanced density of dislocations. The main mechanism of relaxation of residual stresses in overlaid coatings is microtwinning and γ → ɛ transformation.