Additive manufacturing (AM), based on layer-upon-layer building, is continuously proving itself to be a groundbreaking technology, shaking metallurgists into the design of new alloys and complex microstructures.

One of the main restrictions of AM is that thermomechanical or cold working processes are not commonly applied after the manufacturing process, in order to respect the part shape. This limitation forces these routes to be substituted by other hardening procedures based on pure heat treatment and to redefine the alloying strategies. The impossibility to apply cold working is specially challenging when dealing with austenitic stainless steels, because their austenite stability/metastability nature restrains the heat treatment usefulness.

This work proposes the additive manufacturing of a novel high-performance austenitic stainless steel, by means of selective laser melting, with special alloying and microstructural characteristics: high nitrogen content, and composite behavior conferred by an engineered sandwich-like microstructure. Such a design strategy has the purpose to introduce intrinsic heat treatments leading to martensitic transformation during the manufacturing process, in order to achieve an enhanced mechanical response of the material.

This work has been funded by the ComFuturo Third Edition Programme, supported by the Marie Skłodowska-Curie Actions (MSCA) COFUND of the European Commission (Grant Agreement Nº 101034263).