Influence of Powder Characteristics on Processability of AlSi12 Alloy Fabricated by Selective Laser Melting.

Konda Prashanth,Ludmila Radionova,Pavel Lykov,Alexey Shultc,Dmitry Zherebtsov,Rustam Baitimerov

doi:10.3390/ma11050742

Abstract

Selective laser melting (SLM) is one of the additive manufacturing technologies that allows for the production of parts with complex shapes from either powder feedstock or from wires. Aluminum alloys have a great potential for use in SLM especially in automotive and aerospace fields. This paper studies the influence of starting powder characteristics on the processability of SLM fabricated AlSi12 alloy. Three different batches of gas atomized powders from different manufacturers were processed by SLM. The powders differ in particle size and its distribution, morphology and chemical composition. Cubic specimens (10 mm × 10 mm × 10 mm) were fabricated by SLM from the three different powder batches using optimized process parameters. The fabrication conditions were kept similar for the three powder batches. The influence of powder characteristics on porosity and microstructure of the obtained specimens were studied in detail. The SLM samples produced from the three different powder batches do not show any significant variations in their structural aspects. However, the microstructural aspects differ and the amount of porosity in these three specimens vary significantly. It shows that both the flowability of the powder and the apparent density have an influential role on the processability of AlSi12 SLM samples.

Highlights

Selective laser melting (SLM) is one of the metal additive manufacturing (AM) techniques that allows the production of metallic parts from powder feedstock using layer-by-layer approach directly from a computer aided design model (CAD) [1,2,3]
Liu et al has demonstrated that powder of 316L stainless steel with high content of fine particles result in higher powder bed density and in turn generates higher density parts under low laser energy intensity [18]
The influence of the starting powder characteristics on SLM processability of AlSi12 alloy was studied in this paper

Summary

Introduction

Selective laser melting (SLM) is one of the metal additive manufacturing (AM) techniques that allows the production of metallic parts from powder feedstock using layer-by-layer approach directly from a computer aided design model (CAD) [1,2,3]. Materials 2018, 11, 742 fabricated parts strongly depends on the laser processing parameters, building chamber atmosphere, powder bed preheating, and especially on the powder feedstock characteristics [11,12,13]. A significant amount of SLM research has been devoted to optimize the process parameters (laser power, scanning speed, scanning strategy, layer thickness, building chamber atmosphere, powder bed preheating temperature, and post processing heat treatment) and on numerical simulations [2,11,14,15,16]. Spierings et al compared the SLM processing behavior of three 316L stainless steel powder batches with varying particle size distribution and found that fine particles are beneficial for high part densities, process productivity, and scan surface quality [17]. Powder with a narrow particle size distribution leads to better flowability and packing density that generates parts with higher tensile strength and hardness

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Conclusion