Protective and barrier layers play a central role in nature. They protect living organisms from environmental influences and pathogens. One of the outstanding abilities of these systems are self-healing effects [1]. In the current study, the material inherent mechanism of a phase transformation for self-healing in metallic protective coatings is exploited, mimicking the keratinization mechanism of human skin. This mechanism is activated in human body, whenever some external stress is repeatedly applied locally. A similar mechanism can be observed in few metallic materials exposed to mechanical strain. Metastable austenitic steels represent a valuable group of such materials. This steel grades are able to increase their own strength by undergoing local phase transformation austenite → martensite under plastic deformation.

The described mechanism has been thoroughly investigated for a steel 1.4301 as a bulk material, e.g. in cold rolled or hot rolled conditions, in a number of studies [2,3]. However, deformation induced ’ martensite transformation (DIMT) can also be utilized for coatings made of the steel 1.4301, increasing their wear resistance. In the current study, the influence of process parameters of laser cladding process on the microstructure and element distribution of the coating is investigated, since it is of crucial importance for DIMT mechanism. Furthermore, solution heat treatment at T = 1.100 °C has been performed in order to reduce the fraction of delta ferrite in the microstructure of the coatings, as it has a detrimental effect on DIMT. Three point bending tests were implemented to validate the ability of the coatings to undergo martensitic transformation by achieving certain stress values. The extent of microstructure transformation was then investigated by means of light and electronic microscopy. The comparative hardness measurements were conducted in deformed and undeformed regions of the coatings.

The conducted solution heat treatment lead to dissolution of delta ferrite in the coating, setting a completely austenitic microstructure. This enabled a deformation induced martensitic transformation under 3-point bending test conditions.