Engineering Ceramics: Microstructure-Property-Performance Relations and Applications: On-Demand Mechanical Properties of Engineering Ceramics/Applications
Sponsored by: ACerS Engineering Ceramics Division
Program Organizers: Young-Wook Kim, University of Seoul; Hua-Tay Lin, Guangdong University of Technology; Junichi Tatami, Yokohama National University
Friday 8:00 AM
October 22, 2021
Room: On-Demand Room 4
Location: MS&T On Demand
Session Chair: Junichi Tatami, Yokohama National University; Eita Tochigi, University of Tokyo
Invited
In Situ and Atomic-scale Investigations of Mechanical Responses in Oxide Crystals: Eita Tochigi1; 1The University of Tokyo
Plastic deformation and fracture of crystals are originated from generation of lattice defect such as dislocations, twins and cracks under a mechanical stress. It is important to understand their behavior upon loading. In situ transmission electron microscopy (TEM) mechanical testing is a powerful technique to observe mechanical response of lattice defects. In this study, we investigate the mechanical responses of oxide crystals from nano to atomic scale. Firstly, the behavior of deformation twinning in sapphire (α-Al2O3) is discussed. In situ nanoindentation and scanning TEM revealed that the twin propagation occurs by glide of step structures on the matrix/twin interfaces. Secondly, we introduce our custom-made loading device fabricated by micro electro mechanical system (MEMS) technique. This device has a good stability and loading resolution, and thus it is capable of performing atomic-resolution in situ TEM mechanical testing. Some results of in situ observations obtained using the loading device will be shown.
Invited
Triboluminescence of AlN:Mn and CaAlSiN3:Eu Ceramics: Junichi Tatami1; Kentaro Iwai1; Motoyuki Iijima1; 1Yokohama National University
Triboluminescence, which is light emission by friction and wear, is being considered for application to sensors, security, energy conversion, and so on. In this study, triboluminescence of CaAlSiN3:Eu and AlN:Mn ceramics was investigated. Triboluminescence of these materials intensity increased with an increase in the wear volume because the triboluminescence resulted from the fracture of the materials. In particular AlN :Mn ceramics showed better luminescence than CaAlSiN3:Eu ceramics, and luminescence even without wear. Furthermore, triboluminescence intensity of AlN:Mn increased with a decrease in the oxygen in AlN lattice and the quantity of Mn.
Cancelled
Strengthening and Toughening of Titanium Boride (TiB) Ceramic Material by Metallurgical Control of the Composition of Metallic Phase: Jun Du1; K. S. Ravi Chandran1; 1University of Utah
Titanium boride (TiB) has recently emerged as a new ceramic base for structural ceramics with high strength and toughness, competing with the well-known structural ceramics. It is shown here that a significant improvement in the fracture toughness of TiB ceramic alloys, without a loss in strength, can be achieved by controlling the composition of the metallic phase, specifically, the oxygen and iron levels in the beta-Ti phase. The reduction in O and Fe content lead to a notable increase in flexural strength (~933 MPa) and fracture toughness (~8.7 MPa√m). Further reduction in Fe and adding Al increase fracture toughness (~9.6 MPa√m) without a significant loss in strength (~890 MPa). These properties exceed that of well-known ceramics such as Si3N4, TiB2, etc therefore the TiB ceramic is competitive. The complex metallurgical factors that control the strength and toughness of TiB ceramic alloys are discussed.
Nonlinear Continuum Damage Model for Unidirectional Laminate Based Ceramic Matrix Composites: Craig Przybyla1; Jean-François Maire2; Emmanuel Baranger3; Frédéric Laurin2; 1Air Force Research Laboratory; 2Office National d'Etudes et de Recherches Aérospatiales (ONERA); 3ENS Paris-Saclay
The use of continuous fiber reinforced ceramic matrix composites (CMCs) has recently rapidly accelerated, particularly in aero-propulsion. For example, GE Aviation has successfully certified their 2400F SiC/SiC CMC shroud in the CFM International LEAP® engine and an Ox-Ox mixer, center body and cowl cover for the new GE Passport engine (J. Steibel, American Ceramic Society Bulletin, Vol. 98, No. 3). However, despite the recent success of the implementation of advanced CMCs in new systems, damage models to support the design, certification and sustainment of safety critical CMC components are lacking. Here we propose a simple but robust formulation for a two-dimensional continuum damage model derived via a thermodynamics-based approach. Specifically, we account for damage due to matrix cracking in both the fiber and transverse directions. The process of model calibration, verification and validation is discussed. The model is implemented using nonlinear laminate theory to analyze unidirectional laminate-based CMCs.
Mechanical Properties of Nanocrystalline Ceramics: Heonjune Ryou1; Kevin Anderson1; John Drazin2; Edward Gorzkowski1; Boris Feygelson1; James Wollmershauser1; 1U.S. Naval Research Laboratory; 2Washington State University
New development of ceramic processing techniques in recent years have created nanocrystalline ceramics with extremely small grain sizes: below 100 nm. Many studies have reported the extent of the mechanical property improvement in nanocrystalline ceramics with extremely small grain sizes. However, the resulting mechanical properties depends on many aspects of processing and testing methods. In this presentation, various nanocrystalline ceramics with grain sizes below 100 nm were characterized with indentation and flexural testing. Regardless of test methods, nanocrystalline ceramics show the Hall-Petch strengthening of nanocrystalline ceramics but the results are influence by the sample processing, geometry, surface roughness, as well as test geometry. The challenges of performing the tests for nanocrystalline ceramics arise from the nature of nanocrystalline ceramics and current manufacturing techniques.
TiB2-TiC Based Materials with Fine Microstructure and Improved Mechanical Properties: Zhezhen Fu1; 1University of Wisconsin Platteville
A group of TiB2-TiC based composite materials with fine microstructures and improved mechanical properties were developed for structural applications. First, a novel carbon coating precursor method was utilized to synthesis ultra-fine TiB2 and TiC powders with high purity. The synthesized powders were further used to process cermet materials with various metal additives such as Ni, Co, and high-entropy alloys. Due to the advantages of the fine particle size and high purity of the synthesized powders, the composite materials can be densified to high relative densities at lower temperatures (lower up to 300°C). The materials also have very fine grain size and unique microstructures (e.g. elongated grain structure due to the unique grain growth mechanism). Due to such microstructures, the materials have improved mechanical properties such as hardness, fracture toughness, and flexural strength. The materials also show superior nanomechanical properties including hardness and elastic modulus than commercial cemented carbide.
Atomistic Modelling of Dynamic Failure in Boron Carbide: Multi-scale Modeling for Materials Design: Junhao Chang1; Benhour Amirian1; Matthew Guziewski2; James Hogan1; 1University of Alberta; 2Army Research Laboratory
In this presentation, we present a multi-scale modelling approach to design boron carbide materials for improved performance in extreme conditions. Here, we are focused on understanding the influence of microstructural features (e.g., defects, secondary phases, internal disorder, cracks) on the dynamic mechanical response of the materials. Our modelling approaches utilizes Molecular Dynamics, where efforts are given to validate unit cells, potentials, stable states, and energies to improve model stability and accuracy. Once validated, mechanical responses are explored under different stress states, including elastic constants (e.g., Young’s modulus and Poisson’s ratio), peak strength, and fracture energy contributions during loading and failure. Considerations are given for how model outputs compare with experimental data and theoretical models. Once validated and responses are computed, the model is bridged with Phase field and Finite Element modelling efforts. A discussion of the results is provided in terms of materials design, and multi-scale modelling and scale bridging.
Characterization of Clay Ceramics from Areas Near to the Thar Desert, India: Towards Water Filtration Application: Sunil Duhan1; Meraj Warsi1; Himanchal Bharadwaj1; Pankaj Jakhar1; Amrita Nighojkar1; Vinayak Shedekar2; Anand Plappally1; 1IITJ; 2The Ohio State University
Clayey materials from three locations of Western Rajasthan (Jheepasni and Gajsinghpura in Jodhpur district, and Raithal, Jalore district) in India have been studied with the aim to optimize local ceramic water filters named G filters. All composites precursor samples of these functional porous ceramics were composed of 50% by volume of sawdust. A 2 mm x 2mm sieve is used to control the sizes of the raw materials. Composites are press formed to 3l frustum shaped greenwares. Air dried for a week, these greenwares are sintered at 750oC for producing ceramic water filters. Mineralogical investigations using XRD revealed traces of MgO and different salts in all the three ceramics. Stress intensity and compressive strength of these ceramics is studied in relation to grain boundary variations with variation in sintering temperatures. The characterization reveals adaptability of distinct clayey materials towards getting effective filtration rates beyond 1l/h from these water filters.