Method for manufacturing a multi-material part by additive manufacturing, using the technique of powder bed selective laser melting or selective laser sintering

A process for manufacturing a multi-material part by additive manufacturing, said process comprising the following steps:

• a) a step of providing a pre-treated metal powder comprising grains and an oxidized and porous layer on a surface of said grains;
• b) a selective laser powder-bed fusion step comprising implementation of steps i) and ii) as follows:
• i) a step of forming a layer from the pre-treated metal powder;
• ii) a step of melting by laser all or some of said layer of pre-treated metal powder, said melting step being carried out under a reactive atmosphere and said melting step comprising changing parameters of application of the laser so that at least a first region of said layer of pre-treated metal powder is converted so as to lower the electrical conductivity thereof, thus forming a dielectric, and so that at least a second region of said layer of pre-treated metal powder is densified without being converted,
• the at least a first region being formed when the parameters of application of the laser allow a first energy density (Q1) to be applied to said first region and/or the laser beam to be kept for a first dwell time (t1) on said first region,
• the at least a second region being formed when the parameters of application of the laser allow a second energy density (Q2) to be applied to said second region and/or the laser beam to be kept for a second dwell time (t2) on said second region, and
• the first energy density being higher than the second energy density and/or the first dwell time being longer than the second dwell time.