Light Metal and Composites Technology: Composites I: Microstructure and Mechanical Properties
Sponsored by: TMS: Materials Characterization Committee
Program Organizers: Ramasis Goswami, Naval Research Laboratory; Xiaoming Wang, Purdue University; Alex Moser, Naval Research Laboratory; Alan Luo, Ohio State University; Manoj Kolel-Veetil, Naval Research Laboratory; Kumar Sadayappan, CanmetMATERIALS; Tanjore Jayaraman, United States Air Force Academy
Monday 8:00 AM
November 2, 2020
Room: Virtual Meeting Room 28
Location: MS&T Virtual
Session Chair: Ramasis Goswami, US Naval Research Laboratory; Tanjore Jayaraman, University of Michigan
8:00 AM
Introductory Comments: Light Metals and Composite Technology: Ramasis Goswami1; 1Naval Research Laboratory
Introductory Comments
8:05 AM Invited
Joining of Light Metals to Polymer Composites by Overcasting Technique: Aashish Rohatgi1; Kumar Sadayappan2; 1Pacific Northwest National Laboratory; 2CANMET Materials
While light metals and carbon fiber reinforced polymer (CFRP) composites individually offer attractive mechanical performance, fabricating a robust metal-CFRP joint can be challenging. This presentation will describe a technique to join alloys to CFRP by casting the alloy (e.g. Al or Mg) such that a section of the CFRP is completely embedded within the casting to create a strong mechanical interlocking joint. Thus, even though the polymer melting/degradation temperature is several hundred degrees below the casting temperature, the CFRP can survive the overcasting process if the process duration is “short” by maintaining a high cooling rate during the casting solidification (e.g. akin to high-pressure die casting). In this work, overcasting process was performed using continuous and chopped fiber composites. Test coupons were tested in tension and characterized by non-destructive and microscopy techniques. Details of the experiments, the metal-composite interface and the resulting mechanical properties of the joints will be described.
8:25 AM Invited
Nanostructured Composites via Environmentally Controlled Pressure Assisted Sintering: James Wollmershauser1; Boris Feigelson1; Kevin Anderson2; Benjamin Greenberg2; Kedar Manandhar3; Heonjune Ryou1; Edward Gorzkowski1; 1U.S. Naval Research Laboratory; 2National Research Council Postdoctoral Research Fellow sited at U.S. Naval Research Laboratory; 3University of Maryland
Advanced metallic and ceramic composites often require controlled chemical mixing of phases that allows for specific microstructures which enhance functional properties such as exchange coupling in magnetic systems, and fracture resistance, strength, and hardness in composite structural ceramics. NRL’s Environmentally Controlled Pressure Assisted Sintering (EC-PAS) utilizes high pressures to retard bulk diffusion and phase mixing while simultaneously encouraging fast densification by means of contaminate-free high-surface-energy nanoparticles to produce dense nanostructured materials. The talk will focus on EC-PAS processing and properties of a SmCo-Fe exchange-coupled magnetic composites made from mixed powders and a hard transparent ceramic made from spinel/alumina core/shell nanoparticles. The two cases show the capability of NRL’s sintering technique to control microstructure and properties of the dense nanostructured composites.
8:45 AM Invited
Poly(Carborane-siloxane-(aryl)Acetylene)s: A Versatile Inorganic-Organic Polymer Platform for Advanced Materials Applications: Manoj Kolel-Veetil1; 1Naval Research Laboratory
Poly(carborane-siloxane-(aryl)acetylene)s or PCSA(A)s have been extensively developed in the author’s lab and they provide a platform for advanced functional materials development that is unmatched by a single group of polymers. Myriad applications include their utility as thermal (TBCs) and environmental (EBCs) barrier coatings for polymer matrix composites (PMCs) and for electrically insulating polymers such as polyimides, whereby insulative and thermo-oxidative protections are imparted to the adherent substrate. PCSA(A)s have rheological properties that are optimal for infusion processes facilitating processing of ceramic matrix composites (CMCs). Furthermore, in combination with ultrahigh temperature ceramics, they can provide improved electromagnetic wave-absorbing composites for advanced aerospace and electronic applications. Also, the three distinct functional components, i.e. carborane, siloxane and aromatic carbon, afford them an ability to form products spanning inorganic, organic, polymer, ceramic and metallic regimes. New ML/AI approaches to further catalyze the development of these versatile polymers and their derivatives will also be discussed.
9:15 AM
Microstructure, Interfaces, and Mechanical Properties of Ceramic Matrix Composites: Alex Moser1; Ramasis Goswami1; 1Naval Research Laboratory
Incorporation of B4C in metals and alloys is known to enhance the material specific strength and reduce density. A critical factor to improve the mechanical properties of these composites is the bonding strength of the metal/ceramic interface. We investigate the microstructure and interfacial characteristics of B4C-Ni and SiC-B4C composites processed in the solid state at relatively high pressure and low temperature using several methods. Improved hardness and modulus were observed in sintered B4C-Ni powder and attributed to the formation of Ni4B3 at the Ni/B4C interface. Fine probe EDS and HAADF revealed a Si rich intermixing layer at the SiC/B4C interface, which could enhance interfacial strength. The density functional theory (DFT) calculations show SiC-B4C (without intermixing) decohesion energy is the smallest at the interface as compared to the bulk SiC and B4C, and structural failure would occur along the interface.
9:35 AM
Functional Relationships between Treatment Time, Microstructure and Mechanical Properties of Ultrasonically Cast Metal Matrix Nanocomposites: Tanaji Paul1; Cheng Zhang1; Benjamin Boesl1; Arvind Agarwal1; 1Florida International University
Establishment of a quantitative understanding of the effect of ultrasonic treatment variables is essential for the development of process maps for metal matrix composite manufacturing. This paper presents novel mathematical correlations to predict grain refinement and hardening in SiC nanoparticle reinforced Al matrix composites as a function of ultrasonic treatment time. Excellent grain refinement efficiency of 62.8% was achieved by ultrasonication for 90s. This was due to an increase in number of heterogeneous nucleation sites from the synergistic effect of ultrasonic treatment induced microbubbles and SiC deagglomeration. The resulting volumetric nucleation density manifests slow exponential increase with ultrasonication time. Relationships of hardening with time were established by separating grain refinement and SiC dispersion contributions towards hardness. Ultrasonication induced SiC dispersion decreased the interparticle distance with resultant exponential hardening with time. These functional relationships constitute a major advancement towards metal matrix composite manufacturing technology.
9:55 AM
Microstructure and Interfaces of Nanocomposites Manufactured in Solid State: Ramasis Goswami1; 1Naval Research Laboratory
Al2O3 and B4C are the armor grade ceramic materials with considerably high compressive strength and Hugoniot elastic limit (HEA). Studies indicate a few percent total weight reduction can lead to a several percent increase in mobility and survivability. Considerable efforts have been made to manufacture metal matrix composites (MMCs) to enhance the mechanical properties by adding various volume fractions of B4C or SiC powder to achieve higher homogeneity of ceramic particles in the matrix. Here we present the recent development of Al/B4C and Cu/Al2O3 MMCs processed in the solid state. In all cases, the composites show higher hardness as compared to the base metals and alloys. We investigate the microstructure and interfacial characteristics of the composites processed at relatively high pressure using x-ray diffraction (XRD) and transmission electron microscopy (TEM), and demonstrate that the formation of interfacial phase during sintering improves interface cohesion and mechanical properties significantly.
10:15 AM Invited
Revisiting Phase Field Simulations of Theta’ Variant Selection during Stress Aging of Al-Cu Alloys: Bala Radhakrishnan1; Amit Shyam1; 1Oak Ridge National Laboratory
A review of literature on the variant selection of theta’ prime during stress aging of Al-Cu alloy shows conflicting results. Eto et al. (Acta metallurgica, 1978) show that external compression along [001] promotes (001) variants. Phase-field simulations of Li and Chen (Acta. Mater., 1998) are in agreement with the above finding. However, Chen et al. (Materials Char. 2018) indicate that applying compression results in the elimination of the (001) variants. Recent experiments by Guo et al. (J. Alloys Compounds, 2020) show that edge dislocations forming during stress aging reduce the tendency for preferential formation of (001) variants under compression. We present large scale, three-dimensional, phase field simulations of theta’ variant selection in the presence of external load, with or without dislocation strain fields in order to address the above discrepancy. Research funded by the Department of Energy’s Vehicle Technology office at the Oak Ridge National Laboratory under contract DE-AC05-00OR22725.