Development of ideal processing parameters for powder bed fusion system processing of AlSi10Mg using design of experiments

Abstract

The additive manufacturing of aluminium alloys has gained great interest in the transport industry in the past 10 years. This is mainly due to the lightweight and good strength that these alloys offer especially for applications in aerospace and other related industries. However, there is a drawback in using these alloys especially the parts produced by additive manufacturing as they have to be heat treated before application to relieve residual stresses caused by the fast heating and cooling experienced during powder bed fusion (PBF) fabrication. Most of the current PBF metal system offer a variety of processing parameters for part building, however AM uptake and industrial implementation is still slow due to restrictions of the laser power and laser interaction time that are slow and thus the parts take long to produce. Seeing this lag in the market, the CSIR has produced a high speed and high power PBF machine with a build platform larger than the currently available commercial systems. This system allows for the faster production of parts due to its higher consolidation rate and it has already been validated for aluminium alloys, specifically AlSi10Mg. The properties evaluated were microstructure and hardness, which found to be comparable to commercial PBF machines. The samples were analysed for microstructure, mechanical properties using tensile testing procedure. In order to determine that ideal processing window, the response surface methods was used on the Stat-Ease Design Expert software using ultimate tensile strength, elongation and hardness as outputs. Based on the data analysed, the processing window was narrowed to 1400 W laser power and 1.63 - 1.95 s interaction time.