Optimization of selective laser melting modes of powder composition of the AlSiMg system

Abstract

Introduction. New aluminum-based powder systems are currently being developed for additive manufacturing. The scientists' work is aimed at comprehensive studies of powder production, optimization of conditions for alloy production and formation of three-dimensional specimens with minimal porosity and absence of cracking during selective laser melting. The purpose of this work is the synthesis of an almost spherical Al-Si-Mg composite powder (91 wt. % Al, 8 wt. % Si, 1 wt. % Mg) from aluminum powder PA-4 (GOST 6058-22), silicon powder (GOST 2169-69) and magnesium powder MPF-4 (GOST 6001-79), which were not originally intended for selective laser melting technology. The work also provides for the optimization of selective laser melting modes to obtain an alloy and form three-dimensional specimens with minimal porosity and no cracking. To create a powder composition, powders ranging in size from 20 to 64 μm were selected by sieve analysis and subjected to mechanical mixing in a ball mill in a protective argon medium for one hour. The research methods are methods of X-ray diffraction and X-ray phase analysis, transmission electron microscopy, mechanical tests of microhardness. Studies of the powder composition after mechanical mixing showed that the mixed powder of aluminum, silicon and magnesium is a conglomerate of particles of spherical, oval and irregular shape. Results and discussions. The optimal modes for obtaining a specimen with a minimum porosity of 0.03 % and a microhardness of 1,291 MPa are selective laser melting modes: P = 90 W, V = 225 mm/s, S = 0.08 mm, h = 0.025 mm. The conducted research shows the possibility of synthesizing products from metal powders that are not adapted to processing by selective laser melting and obtaining an alloy with new mechanical properties during laser action.