Aluminum Alloys, Characterization and Processing: Additive Manufacturing
Sponsored by: TMS Light Metals Division, TMS: Aluminum Committee
Program Organizers: Julie Levesque, Quebec Metallurgy Center; Stephan Broek, Kensington Technology Inc
Wednesday 2:00 PM
March 22, 2023
Room: 32A
Location: SDCC
Session Chair: Mohsen Mohammadi, University Of New Brunswick
2:00 PM
Compatibility Study of Polymeric Binders for Aluminum Binder Jet Parts: Solgang Im1; Rasim Batmaz2; Arunkumar Natarajan1; Etienne Martin3; Apratim Chakraborty2; 1GE Additive; 2University of Waterloo; 3Polytechnique Montreal
Binder jetting of aluminum powder has progressively gained the interest of automotive and aerospace industries for the fabrication of lightweight products. However, the interactions between the polymeric binders and oxidative behavior of aluminum powder have not yet been extensively studied by researchers. Hence, this research focuses to understand the impact of polymeric binders on the final quality of the aluminum samples by analyzing the level of impurities and densification. Five binders were prepared to fabricate green state samples with the AlSi10Mg powder. The lowest level of impurities was obtained with the alcohol solvent-based binders while moderate to high binder residues were reported with the organic solvent and water-based binders. In addition, the highest sintered density of 95.1% was achieved using the alcohol solvent-based binder, whereas the water-based binder delivered the lowest sintered density. Therefore, this research recommends the PVP binder as the most suited binder among the considered binders.
2:25 PM
Material Evaluation Framework of Additive Manufactured Aluminum Alloys for Space Optical Instruments: Zachary Post1; Walter Zimbeck1; Steven Storck1; Floris van Kempen2; Gerard Otter2; John Boldt1; Ludger van der Laan2; Steven Szczesniak1; Ryan Carter1; Robert Mueller1; Salahudin Nimer1; Doug Trigg1; Michael Berkson1; Frank Morgan1; William Swartz1; 1JHU APL; 2TNO
A framework for additive manufactured alloy selection was developed to determine the preferred aluminum material for the Compact Hyperspectral Air Pollution Sensor (CHAPS). A number of high strength laser powder bed fusion (L-PBF) aluminum alloys have become commercially available with much higher tensile strength than the standard L-PBF AlSi10Mg alloy. These alloys (7A77, A20X, Scalmalloy, and 6061-RAM2C) were compared by defining weighted CHAPS-specific criteria and binning test results into scoring categories to produce a quality score for each alloy and parameter set. Round 1 identified parameter sets that produced material with high density and tensile properties. Round 2 focused on print quality of the seven best parameter sets using geometries representative of CHAPS design features. Round 3 assessed build orientation anisotropy and compatibility with mirror processing steps of the best laser parameter set. Scalmalloy had the best quality score and was used to print topology optimized housings and lightweighted mirrors.
2:50 PM
Comparison of Additively Manufactured and Cast Aluminum A205 Alloy: Heidar Karimialavijeh1; Morteza Ghasri Khouzani2; Apratim Chakraborty2; Jean-Philippe Harvey1; Etienne Martin1; 1Polytechnique Montreal; 2University of Waterloo
The relationships between the microstructure and thermal behaviour of additively manufactured and cast aluminum A205, a recently developed Al-Cu-Mg-Ag-TiB2 alloy, were investigated. Microstructural characterization performed using scanning electron microscopy (SEM) indicated a significant difference in grain size between laser powder bed fusion (LPBF) and cast specimens. Ultrafine round intercellular precipitates were observed in the LPBF structure, while intergranular precipitates were found in the cast structure. Trans-cellular TiB2 particles were observed in the LPBF structure, while accumulated intergranular TiB2 particles were found in the cast structure. Moreover, X-ray diffraction analysis revealed a higher fraction of precipitates in the LPBF specimen compared to the cast specimen. This was attributed to extremely high cooling rates which extend the solubility of alloying elements in the matrix. The thermo-analytical study demonstrated a strong correlation between the microstructural scale and precipitate dissolution kinetics of A205. The higher diffusion rate inherent in refined microstructures facilitates the dissolution of precipitates in the LPBF A205.
3:15 PM
The Role of Ti and B Additions in Grain Refinement of Al-Mn Alloy during Laser Additive Manufacturing: Qingyu Pan1; Monica Kapoor2; Sean Mileski2; John Carsley2; Xiaoyuan Lou1; 1Purdue University; 2Novelis Global Research and Technology Center
While adding Ti and B to Al alloys is the proven method for grain refinement, the actual mechanism is still under debate. In the present work, we investigated the governing mechanism of Ti and B additions to grain refinement in AA3104 Al-Mn alloy during laser direct energy deposition (DED) additive manufacturing (AM). The microstructure development and phase transformation of DED AM AA3104 were studied after adding different fractions of Ti, B, Ti-B mixture, and TiB2 particles. The transition from large columnar grains to fine equiaxed grains was observed after Ti and Ti-B addition, but not after B and TiB2 addition. The high fraction of alloy additions were required to develop effective grain refinement. The roles of intermediate species Al3Ti and TiB2 particles during laser solidification were characterized by synchrotron X-ray, SEM, and optical image analysis.Al3Ti was confirmed to play a dominating role in grain nucleation during DED AM.