Metal-Matrix Composites: Analysis, Modeling, Observations and Interpretations: Analysis and Characterization Techniques
Sponsored by: TMS Structural Materials Division, TMS: Composite Materials Committee
Program Organizers: Srivatsan Tirumalai; Yuzheng Zhang, Gamma Alloys; William Harrigan, Gamma Alloys
Tuesday 2:00 PM
February 25, 2020
Room: 31A
Location: San Diego Convention Ctr
Session Chair: Tirumalai Srivatsan, The University of Akron
2:00 PM Invited
Volume Fraction Analysis of Alumina Reinforced Aluminum Composites: William Harrigan1; 1Gamma Alloys
The analysis of any composite requires information about the amount of reinforcement present. A common way to determine the amount of reinforcement is to dissolve the matrix and then weigh the remaining reinforcement. The first requirement for this analysis is that the solution used to dissolve the matrix in inert to the reinforcement. For aluminum matrix composites containing aluminum oxide as the reinforcement, this is not possible with common reagents. The common solutions for dissolving aluminum alloys contain Hydrofluoric acid, which dissolves aluminum oxide. Another way to determine the amount of reinforcement is the measure the elastic modulus of the composite and then calculate the amount of reinforcement that leads to that modulus. This paper discusses a method for measuring the elastic modulus for particle reinforced aluminum composites. The method for calculation of the elastic modulus for particle reinforced aluminum will also be discussed. Data will be presented.
2:30 PM Invited
4D X-ray Tomography and Correlative Microscopy of Composite Materials: Nikhilesh Chawla1; 1Arizona State University
Characterization of composite materials is often conducted by mechanical testing followed by laborious cross-section, characterization, etc. X-ray tomography provides a wonderful means of characterization damage in composites non-destructively. In this talk, we report on the critical link between microstructure and deformation behavior, by using a three-dimensional (3D) virtual microstructure obtained by x-ray synchrotron tomography, as well as focused ion beam imaging. The approach involves capturing the microstructure by in situ thermal and mechanical cycling in an x-ray synchrotron, followed by x-ray tomography and image analysis, and 3D reconstruction of the microstructure. We present results on thermal cycling and mechanical fatigue of SiC particle reinforced Al alloy matrix composites. In particular, the evolution of damage in the form of particle fracture, interfacial debonding and crack deflection, and void growth will be described. Characterization and in situ testing results in nanolaminate Al/SiC composites will also be presented.
3:00 PM
Synthesis and Characterization of In-situ Formed TiB2 Particulate Reinforced Al-Si Alloy Composites: Jimmy Karloopia1; Shaik Mozammil1; Pradeep Jha1; 1Indian Institute of Technology Roorkee
Al-Si alloy reinforced with TiB2 particles (2, 5 and 7 wt.%) were synthesized successfully using stir casting method. K2TiF6 and KBF4 salts were used to obtain in-situ TiB2 phase in molten matrix. These in-situ composites have shown significant improvement in their mechanical properties such as yield strength, young’s modulus and micro hardness as compared to the base alloy (Al-12%Si). X-ray diffraction patterns of the obtained metal matrix composites confirms the formation of TiB2 particles. The microstructures were studied using field emission scanning electron microscopy. The in-situ formed TiB2 particles were found uniformly distributed with good interfacial bonding. Reinforcement particles were predominantly in cubical, spherical and hexagonal shapes. Fracture surface of composites contained fine dimples and some microcracks were generated and propagated through cleavage or facets zones.
3:30 PM Break
3:50 PM
Processing and Microstructural Characterization of Novel Invar Syntactic Foams: Justin Whetten1; Arun Sundar1; Jason Williams1; Scott Roberts2; Nikhilesh Chawla1; 1Center for 4D Materials Science, Arizona State University; 2NASA/JPL
Metal matrix syntactic foams (MMSF’s) have been extensively studied due to their remarkable weight reductions and higher specific strengths. MMSF’s are commonly achieved via hollow microspheres that control pore geometry and low melting point metals like magnesium an aluminum. Invar matrix composites with hollow glass microspheres were fabricated and characterized. An electroless nickel coating process was used on the glass microspheres to improve the strength and a means for interfacial bonding with the matrix. 3D X-ray nanotomography was employed to study the microstructure of the new syntactic foam non-destructively at varying volume fractions and nickel thickness. Mechanical characterization was coupled with microstructure data from 3D X-ray nanotomography and SEM imaging to understand the system thoroughly and will be discussed.
4:15 PM
Design of Steel Microstructures by Manipulation of Reinforcement Precipitates using Finite Element Methods: Samuel Schwarm1; 1Naval Surface Warfare Center Carderock Division
Advancements in the development of computational tools continue to increase the scope of modeling capabilities and change the fundamental aspects of alloy design. The ability of finite element method (FEM) modeling to capture fundamental stress and strain interactions at multiple length scales makes it a useful tool for analysis of micromechanical phenomena such as stress transfer, yielding behavior, etc. within multi-phase metallic structures. This work utilizes FEM models of microstructures as a tool for optimizing steels for improved mechanical performance by analyzing the effects of ceramic or intermetallic particulate reinforcements. These models are used to predict the effects of changing morphologies, distributions, and volume fractions within an austenitic matrix. FEM predictions can be used as part of an iterative integrated computational materials engineering (ICME) alloy design process to reduce requirements of experimental iteration and significantly reduce the time required to develop new alloys to meet challenging design requirements.
4:40 PM
Mechanical Testing of Steel and Tungsten Fibers for Use in Composites for Fusion Applications: Matthew Weinstein1; Lauren Garrison2; Maxim Gussev2; Carol Lin3; Johann Riesch4; 1University of Wisconsin-Madison; 2Oak Ridge National Laboratory; 3University of Illinois Urbana-Champaign; 4Max-Planck-Institut für Plasmaphysik
Although tungsten materials exhibit many good qualities in environments characteristic of fusion reactors, they suffer from low toughness and are brittle. One way to overcome this is with the use of tungsten fiber composites. In order to implement these fiber composites in use as a fusion reactor component, it is necessary to understand the constituent materials that makeup the fiber composite. To do this, tungsten fibers with 150 μm diameter and 40 mm length were tensile tested at room temperature in conjunction with digital image correlation (DIC) to better understand the tungsten fibers individually and how they will contribute to the overall properties of the composite material. For comparison, steel fibers of Alloy 304 with 203.2 μm diameter were also tested. The tensile tests required developing a fiber mounting procedure and unique fixture to grip the fiber ends without damage. Additionally, images were taken of the fracture surfaces.
5:05 PM
Lightweight Radiation Shielding Using Metal Matrix Composites: Andrew O'Connor1; Wesley Bolch1; Michele Manuel1; 1University of Florida
Simulating neutron radiation attenuation by the metal matrix and reinforcing particles for neutron absorbing metal matrix composites can guide design and optimize future experimentation. Various metals and their alloys are evaluated as the matrix with respect to neutron shielding ability. Neutron transmission simulations using the Japan Atomic Energy Agency's PHITS radiation transport code predict the macroscopic cross-section for neutron absorption. The results illustrate how particle size and associated volume fraction affect the radiation shielding ability of metal matrix composites. It is anticipated that this data can be used to select an appropriate metal matrix and particle size and volume fraction for structural materials used in aerospace and other high radiation environments.