Proceedings Article | 12 March 2024
KEYWORDS: Metals, Copper, Temperature distribution, Materials properties, Laser irradiation, Computer simulations, Additive manufacturing, Spatial light modulators, Emissivity
Selective Laser Melting (SLM) technology has been widely used in various applications for aerospace, biomedical, molding and tooling, and automotive, etc. One of the key fundamental problems of the SLM is homogeneity of the manufactured structures, a roughness of their surface and precision of their sizes, which is strongly dependent on the material absorption coefficient that, in turn, depends on a wavelength of the laser radiation, and temperature, etc. Solution of this problem defines a success of SLM production in future its applications. Evidently, if a material under manufacturing, for example, consists of two different metals, then a temperature, stress and strain of these metals will differ because of strong dependence of the material’s absorptivity on a wavelength of laser radiation. As a result, after their solidification, one can expect an appearance of a crack or strain, at least. To avoid these disadvantages, we propose to irradiate the metals simultaneously by optical pulses with two different wavelengths. At corresponding choice of the laser pulses’ incident intensities, the temperature difference of the metals may decrease and heating (or stress, or displacement) of the metals will tend to more homogeneous one. To show this opportunity, we do a computer simulation of heating the 3D bimetallic plate, produced from Cu and a steel 316L, by irradiating the laser beams with wavelengths of 1060 nm and 515 nm separately and simultaneously. We account for the thermal conduction between Cu and 316L, and heat transfer to the substrate by copper and steel 316L respectively, the heat losses due to convection and radiation mechanisms from the metal domain to the environment as well as temperature-dependent thermophysical properties of the materials. Analyzing distributions of the temperature, stress, and displacement in the bimetallic plate, we analyze an efficiency of the dual-wavelength beams' action on improving the stress and deformation of the bimetallic plate under the SLM processing.
