Browsing by Subject "microscale"

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A NOVEL COATING METHOD USED TO ENABLE MULTILAYER STRUCTURES WITH MICROSCALE SELECTIVE LASER SINTERING
(University of Texas at Austin, 2023) Liao, A.; Behera, D.; Cullinan, M.A.
The microscale selective laser sintering process (µSLS) is an additive manufacturing technique that enables the creation of metal features with sub-5 µm in-plane resolution. In this process, a layer of metal nanoparticle ink is deposited onto a substrate and positioned beneath an optical subsystem with a nanopositioning stage. Using a digital micromirror device, a laser is spatially modulated to selectively heat up particles in desired regions to cause sintering. The substrate is then moved to a coating station where a new layer of nanoparticle ink is applied atop the sintered features. Initially, the slot-die coating process was adopted as the recoating method for this technique. However, due to challenges with depositing consistent ink thickness across the recoated part and limitations with the minimum layer thickness achievable, a new approach inspired by blade coating has been developed to achieve layer thicknesses of less than 1 µm.
Mechanical Properties of Selective Laser Melted AlSi10Mg: Nano, Micro, and Macro Properties
(University of Texas at Austin, 2015) Aboulkhair, Nesma T.; Stephens, Alex; Maskery, Ian; Tuck, Chris; Ashcroft, Ian; Everitt, Nicola M.
The selective laser melting (SLM) of aluminium alloys is of great current interest at both the industrial and research levels. Aluminium poses a challenge to SLM compared with other candidate materials, such as titanium alloys, stainless steels, and nickel-based alloys, because of its high thermal diffusivity and low infrared absorptivity and tendency to result in relatively porous parts. However, recent studies have reported the successful production of dense AlSi10Mg parts using SLM. In this study, we report on the nano, micro, and macroscopic mechanical properties of dense AlSi10Mg samples fabricated by SLM. Nanoindentation revealed the hardness profile across individual melt pools building up the parts to be uniform. This is due to the fine microstructure and uniform chemical elements distribution developed during the process due to rapid solidification. Micro-hardness testing showed anisotropy in properties according to the build orientation driven by the texture produced during solidification. Lastly, the tensile and compressive behaviours of the parts were examined showing high strength under both loading conditions as well as adequate amounts of strain. These superior mechanical properties compared to those achieved via conventional manufacturing promote SLM as promising for several applications.