2023 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2023): Materials: Metals-Mechanical Properties II
Program Organizers: Joseph Beaman, University of Texas at Austin
Tuesday 10:25 AM
August 15, 2023
Room: 410
Location: Hilton Austin
10:25 AM
A Comparison of the Mechanical Behavior of AlSi7Mg Alloy Produced Through Additive Manufacturing and Subjected to Different Heat Treatment and Aging Conditions: Victor Medrano1; Kevin Caballero1; Edel Arrieta1; Jorge Merino1; Bryan Ruvalcaba1; Brandon Ramirez1; Jacky Diemann2; Lawrence Murr1; Ryan Wicker1; Donald Godfrey3; Mark Benedict4; Francisco Medina1; 1W.M. Keck Center for 3D Innovation; 2SLM Solutions Group AG; 3SLM Solutions NA; 4Air Force Research Laboratory
Aluminum F357 (AlSi7Mg) is a versatile material used in aerospace and defense industries, which undergoes heat treatment for enhancing its mechanical properties. This study fabricated Aluminum F357 specimens using two different laser powder bed fusion systems and subjected them to five different heat treatments, followed by aging at two different temperatures for varying durations. The aged specimens were machined to create tensile specimens that were tested for mechanical properties. The study found that the specimens fabricated in the Z build direction had higher yield strengths than those subjected to HIP and unaged specimens. HIPed components when aged at 177°C for 1000 hours showed lower yield strengths. These results were consistent regardless of the fabrication system used, indicating the compatibility of the LPBF system fabrication. The study provides valuable information for the aerospace and defense industries to optimize their processes and produce high-quality components.
10:45 AM
Experimental Investigations of Inhomogeneous Component Properties in Laser-based Additive Manufacturing of AlSi10Mg: Steffen Czink1; Volker Schulze1; Stefan Dietrich1; 1Karlsruhe Institute of Technology
In the laser-based additive manufacturing (PBF-LB) process of AlSi10Mg components, the layer-by-layer deposition leads to microscopic and macroscopic thermal effects (shrinkage, residual stresses, overheating) depending the component geometry. This results in a strong dependence of the microstructure and therefore of the process-induced material properties on the shape of the manufactured component. To analyze this behavior, components with different geometric aspects, such as various construction angles, were built in the PBF-LB process. In order to perform a spatially-resolved characterization and evaluation of the mechanical behavior of the component, small-scale tensile specimen in the sub-millimeter range were manufactured from representative areas of the components. With the obtained results, design approaches based on local material data can be improved significantly.
11:05 AM
Microstructure and Tensile Properties of Aluminum Alloy 4008 (A356) Processed via Liquid Metal Jetting: Kellen Traxel1; Nicholas Watkins1; Alex Wilson-Heid1; Andrew Pascall1; Jason Jeffries1; 1Lawrence Livermore National Laboratory
Liquid metal jetting based-AM is an emerging process requiring only raw metal ingot to produce near-fully dense parts through jetting molten metal at frequencies as high as 400Hz. While opening a large application space due to a wide array of acceptable feedstock forms, questions about part quality and processability of different materials limit industrial use. Being a non-fusion based AM technique, processing parameters such as buildplate temperature can likely influence part densification, microstructure, and tensile properties, but these relationships are not well understood to date. To this end, we present results of printing studies where aluminum alloy Al4008 was jetted onto metallic substrates at various buildplate temperatures and layer-wise rastering angles to understand their influence on densification, microstructure, and tensile properties. Our results help manufacturers and researchers working to develop non-powder based metal additive manufacturing methods. Prepared by LLNL under Contract DE-AC52-07NA27344. LLNL-ABS-847002.
11:25 AM
Comparison of Layerwise Preheating and Post Heating Laser Scan on the Microstructure and Mechanical Properties of L-PBF Ti6Al4V: Ahmet Tanrikulu1; Aditya Krishna Ganesh Ram2; Behzad Farhang2; Amirhesam Amerinatanzi2; 1University of Texas at Arlington / Turkish Aerospace Industries; 2University of Texas at Arlington
This study aimed to investigate the evolution of the microstructure and mechanical properties of as-fabricated laser powder bed fusion (L-PBF) Ti-6Al-4V samples by introducing layerwise pre-heating or post-heating laser scans. Multiple laser scans, varying in power and scanning speed, were examined before the melting laser scan (pre-heating) or after it (post-heating). The analysis focused on microstructural features such as porosity, lattice structure, phases, and grain size, as well as the tensile response of the material. The results revealed the additional layerwise scans had a significant impact on reducing porosity by up to 98% when the additional scan was applied prior to the melting scan. Post-heating laser scan enhanced the material’s plastic deformation by up to 9%. Furthermore, these findings highlight the potential of layerwise heating strategies to improve the overall quality and performance of L-PBF Ti-6Al-4V components, thus paving the way for enhanced applications in various industries such as aerospace.
11:45 AM
Microtensile Analysis of Additively Manufactured Ti–6Al–4V with Process Parameter Induced Defects: Kourtney Porsch1; 1Johns Hopkins University Applied Physics Laboratory
Additively manufactured Ti–6Al–4V samples, with intentionally induced defects generated by varying the process parameters, were analyzed using microtensile testing techniques. Samples with defects exhibited statistically-significant larger microtensile than macrotensile ultimate strengths. Weibull microtensile moduli are smaller than macrotensile moduli indicating greater variability. Comparing the microtensile results to macrotensile properties reveals how changing these process parameters affects the range of mechanical behaviors potentially present in additively manufactured parts due to the varying microstructures in the material.