October_2021_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | O C T O B E R 2 0 2 1 3 3 AN EXPERIMENTAL STUDY ON MECHANICAL, THERMAL AND FLAME-RETARDANT PROPERTIES OF 3D-PRINTED GLASS-FIBER-REINFORCED POLYMER COMPOSITES Ashish R. Prajapati, Harshit K. Dave, and Harit K. Raval Fused deposition modeling (FDM) is one of the most common 3D print- ing processes. Currently, several mod- ifications have been applied to the FDM process where it can manufac- ture fiber-reinforced polymer compos- ites (FRPC). This paper aims to analyze the mechanical, thermal, and flame- retardant properties of FRPC manu- factured by the FDM process. Polymer composite filament (a mixture of ny- lon polymer and short carbon fibers) is used as a matrix, while fiberglass and high-strength, high-temperature fiber- glass are used as a fiber reinforcement. A MarkTwo 3D printer from Markforged is employed to create the FRPC parts. The change in different mechanical properties, namely, tensile and impact of polymer composite matrix by adding different fibers, is studied. In addition, thermogravimetric analysis, x-ray dif- fraction and flammability testing are also carried out to analyze the thermal properties of composites. MELT POOL AND HEAT TREATMENT OPTIMIZATION FOR THE FABRICATION OF HIGH-STRENGTH AND HIGH- TOUGHNESS ADDITIVELY MANUFACTURED 4340 STEEL Matthew A. Ryder, Colt J. Montgom- ery, Michael J. Brand, John S. Car- penter, Peggy E. Jones, Anthony G. Spangenberger, and Diana A. Lados This study focuses on 4340 steel fabricated using laser powder bed fu- sion (LPBF); 42 laser power and scan speed combinations have been sys- tematically investigated to optimize the melt pool geometry and ensure ful- ly dense parts. The AM material is com- pared with a wrought 4340 equivalent and studied in both as-fabricated and heat-treated conditions. Two heat treat- ments were designed and used to op- timize the materials for strength and toughness, respectively. Microstructure, tensile, and fractographic studies are conducted to assess build integrity and establish processing–structure–perfor- mance relationships. Tensile properties of the AM materials in all studied con- ditions were equivalent or better than the comparable wrought materials. The high performance of the AM materials was attributed to the absence of both manganese sulfide inclusions and roll- ing-induced banding, typically found in the wrought materials. VAT-PHOTOPOLYMERIZATION- BASED CERAMIC MANUFACTURING Xiangjia Li and Yong Chen This article presents a detailed account of the processes involved in vat-photopolymerization-based fabri- cation of ceramics, namely bioceramics, structural ceramics, piezoelectric ce- ramics, optical ceramics, and polymer- derived ceramics. Information and methods of material preparation, cur- ing characteristics, greenpart fabrica- tion, property identification, process design and planning, and quality con- trol and optimization are introduced. The article also provides information on postprocessing techniques, name- ly debinding and sintering, as well as on the phenomenon of shrinkage and compensation. ~AM&P GET ENGAGED, GET INVOLVED, GET CONNECTED Join the conversation about additive manufacturing. ASM Inter- national is exploring the launch of a technical community or commit- tee on additive manufacturing to co- ordinate ASM activities in this area and to provide new collaboration and networking opportunities for members involved in additive tech- nologies. William E. Frazier, FASM, is leading this effort. If you are inter- ested in getting involved, please vis- it ASM Connect and complete a brief volunteer interest form, https://bit. ly/3ESZaO4. ASM HANDBOOKS ON ADDITIVE MANUFACTURING In 2020, the Society published ASM Handbook, Volume 24, Additive Manufacturing Processes, its first full volume on additive technologies. Two additional AM volumes are in development: • Volume 23A, Additive Manufac- turing in Biomedical Applications, planned for release in 2022 • Volume 24A, Additive Manufac- turing Design and Application (publication date TBD) Contact David Vargas at david. vargas@asminternational.org and Amy Nolan at amy.nolan@asminternational. org for details on contributing to Vol- ume 24A. Coverage includes refer- ence papers and case histories in the areas of Design, Metals Process De- velopment (PBF, DED, binder jet), Economic and Business Consider- ations, Material Characterization, In-Situ Monitoring, and Applications (Aviation, Spaceflight, Medical, Auto- motive and Heavy Machinery, Oil/Gas and Maritime, Construction, Energy, Electronics).