Processing and Performance of Materials Using Microwaves, Electric and Magnetic Fields, Ultrasound, Lasers, and Mechanical Work: The Rustum Roy Symposium: Session I
Sponsored by: ACerS Basic Science Division, ACerS Manufacturing Division
Program Organizers: Morsi Mahmoud, King Fahd University Of Petroleum And Minerals; Dinesh Agrawal, Pennsylvania State University; Guido Link, Karlsruhe Institute of Technology; Motoyasu Sato, Chubu University; Rishi Raj, University of Colorado; Christina Wildfire, National Energy Technology Laboratory; Zhiwei Peng, Central South University

Monday 8:00 AM
October 18, 2021
Room: B233
Location: Greater Columbus Convention Center

Session Chair: Daudi Waryoba, Pennsylvania State University

8:00 AM
Assessment of Homogeneity in Percolated Composite Samples: Miriam Rath¹; Rosario Gerhardt¹; ¹Georgia Institute of Technology
    Ceramic composite materials such as SiCw-Al2O3 are used in a wide range of applications ranging from mechanical wear to microwave heating. The electrical properties of these materials have been previously studied as a function of SiCw content and orientation of the whisker long axis with respect to the hot pressing direction. In this study, we have evaluated the variability in electrical response of SiCw-Al2O3 composites at a fixed SiCw content beyond the percolation threshold. Our results indicate that for spark plasma sintered (SPS) materials, the electrical response of the same composition mix can be affected by sample thickness and diameter while using the same SPS conditions. This provides proof that the heterogeneous distribution of the SiCw is more complex than previously anticipated and that electrical measurements may be used as a way to non-destructively assess their microstructural condition. Error analysis to demonstrate the extent of the variability will be presented.

8:20 AM
Freeform Microcasting: Luciano Borasi¹; Enrico Casamenti¹; Raphael Charvet¹; Cyril Denereaz¹; Sacha Pollonghini¹; Lea Deillon¹; Yves Bellouard¹; Andreas Mortensen¹; ¹EPFL
    Metal casting provides a potent approach for the three-dimensional freeform fabrication of metal microcomponents. By combining femtosecond laser micro-machining of glass molds with pressure infiltration, one can overcome limitations of the metal casting process that have hindered its entry into the realm of microtechnology. With this process one can produce combinations of dense metal encased within glass, which can either serve together in microdevices, or can alternatively be used to produce cast metal microparts if the glass mold is selectively dissolved. Dense 3D parts of arbitrary shape, made of silver, copper, gold or their alloys can be made with features of size down to ~1.5 痠, with a potential for production rates that far exceed those of alternative processes that have been developed for the production of dense micron-scale metal parts.

8:40 AM
Electromagnetic Assisted Thermal Processing Enabling Spatially Selective Phase Transformation of Metal Amorphous Nanocomposites: Ahmed Talaat¹; Kevin Byerly²; David Greve²; Michael McHenry²; Paul Ohodnicki¹; ¹University of Pittsburgh; ²Carnegie Mellon University
    Microstructure engineering by means of electromagnetic radiation at extremely high heating and cooling rates can result in unique phase transformation and spatially selective crystallization events in soft magnetic metal amorphous nanocomposites. In this work we explore radio frequency induction heating and laser processing of a range of different alloy systems in order to produce rapid thermal heating profiles enabling nanocrystallization as well as spatially selective microstructures throughout processed strips. Simulation of electromagnetic heating effects and impacts on microstructures and phase transformation upon heat generation were performed. A comparison of traditional and induction annealing approaches based on both direct coil-heating and susceptor-based heating as well as laser heating will be presented along with the results of structural and magnetic property characterization.

9:00 AM
Solid State Joining of Dissimilar Single Crystal Ni-based Superalloys Using Field Assisted Sintering Technology (FAST): Charis Lin¹; Jogender Singh¹; Matthew Hogan¹; Namiko Yamamoto¹; ¹The Pennsylvania State University
    This work demonstrates that two single crystal Ni-superalloys (PWA 1429 and PWA 1480) can be joined in the solid state using FAST without a heat affected zone or localized melting. Microstructural inspection revealed a void-free interface without a sharp interface line, but with some changes in precipitation morphology at the interface due to the chemical composition gradient. Preliminary room temperature tensile testing indicated bonding strengths comparable to that of the parent materials, though fracture occurred at the material interface. Our results show the potential of high-density electric current assisted diffusion bonding for high-strength joining of single crystal Ni-superalloys. FAST opens the door for gas turbine blade repair, including single crystal Ni-superalloys, and eliminates many of the shortcomings of current joining technologies associated with melting processes at the interface, grain recrystallization, and precipitation of carbides and Laves phases, which decrease the alloying elements available for precipitation strengthening.

9:20 AM  Invited
Electric Current Processing of Additively Manufactured Ti-6Al-4V Alloy: Daudi Waryoba¹; Zahabul Islam¹; Ted Reutzel¹; Aman Haque¹; ¹Pennsylvania State University
    Structure-property-processing relationship has been studied in additively manufactured Ti-6Al-4V alloy. The processing was performed in-situ a transmission electron microscope (TEM) using a moderate current density of 5x105 A/cm2, and by suppressing Joule heating such that mechanical properties were not compromised. The results show that while the grain size increased by ~15%, the nanohardness increased by 16%. This is attributed to the pronounced dislocation generation, regeneration, and clustering as well as defect healing. Ultimately, there is a reduction in the residual strain and a significant increase in the intrinsic strength as evidenced by the high Taylor factor of the electric current processed specimen. This novel processing technique presents an alternative pathway for active controlling of microstructure and internal defects for additively manufactured parts that might be sensitive to high temperature processing or other conventional methods.