Boron Nitride Nanotube Reinforced Metal Matrix Composites

Boron Nitride Nanotube (BNNT) displays remarkable mechanical properties (elastic modulus and tensile strength exceeding 1 TPa and 60 GPa, respectively) and brilliant thermal endurance (capable of withstanding temperatures as high as 700-900°C without degrading or oxidizing). This makes BNNT an ideal reinforcement candidate for developing strong and lightweight nanocomposites. This research seeks to integrate BNNT in Aluminum, Magnesium and Titanium matrices to enhance their mechanical properties. Spark plasma sintering and solidification processes (casting, ultrasonic cavitation and plasma spray) are being adopted. In-situ mechanical techniques are being employed for real-time examination of strengthening mechanisms in these nanocomposites.

Directionally Aligned Nanotubes Acting as Crack Bridges in Al-BNNT Composite

Wetting and Filling of Nanotubes by Molten Aluminum during Equilibrium Solidification

Splat Sliding in Cold Sprayed Metallic Coatings

Cold sprayed coatings are composed of splats as their building blocks. Relative sliding between the splats can lead to deterioration of mechanical properties. This project seeks to examine the splat sliding behavior by in-situ mechanical investigations under a scanning electron microscope for real time visualization of deformation behavior. The splat sliding behavior is dependent on splat geometry, porosity, oxide content and inter-splat bonding. This project aims to establish correlation between processing conditions, coating microstructure and mechanical properties, and to understand the role of post-processing heat-treatment on arresting the splat sliding. In-situ techniques such as flexural tests, nanoindentation and nanoscratch in conjunction with Digital Image Correlation (DIC) analysis approach are adopted for visualizing the deformation mechanisms in cold sprayed microstructure.

Microstructural strains determined by in-situ testing inside electron microscope

In-situ testing of cold sprayed metallic coating inside SEM chamber

Graphene Foam

Researchers at the Plasma Forming Laboratory are focusing on the development and characterization of the next generation high-performance Graphene foam (GrF) based composites. The three-dimensional cellular structure in GrF conserves most of graphene’s remarkable properties while offering seamless pathways for mechanical, electrical and thermal transport. Our lab is interested in exploring the multifunctionality that the hierarchical structure of GrF provides to develop lightweight composites with enhanced strength, impact resistance, and sensing capabilities. Research efforts at the PFL include probing the performance of GrF based composites in areas of energy, mechanics, deicing, electromagnetic shielding and health. Studies include the nanoengineering of GrF –polymer interfacial surfaces, and the understanding of fundamental deformation features proving enhanced thermal, electrical and superior load-bearing abilities.

Scanning Electron Micrograph of free-standing three-dimensional Graphene Foam

3D Graphene Foam hollow branch with open cell structure

Ultra High Temperature Ceramics

Ultra High-Temperature Ceramics have been of great interest in the aerospace and aeronautic industry due to the high melting point, and due to their potential application as a protective material for the stagnation areas of leading edges in supersonic vehicles. At the Plasma Forming Lab, researchers are working on the development of the next generation of UHTC’s. Space exploration will have to be reusable, that is one of the main goals on the development of new UHTC’s: durability. With new UHTC’s that will be able to stand multiple reentries from orbital speeds to our atmosphere, man will be able to accelerate space exploration due to the reduction in resources needed to keep exploring. 

Scanning Electron Micrograph of UHTC

Ultra High Temperature Ceramics: one of the key components of space exploration

Ultrasonic Treatment Processing Maps for Metal Matrix Nanocomposites

Researchers at PFL are developing a novel ultrasonic treatment process for manufacturing lightweight, high-strength metal matrix nanocomposites. The strong binding forces at the surface of nanoparticle reinforcements are a severe challenge towards distributing them in a metal matrix. This research seeks to utilize high-intensity acoustic waves to deagglomerate and disperse 1D, 2D and 3D nanoparticle clusters in molten metal during casting. Structural and mechanical characteristics of the nanocomposites are being probed from macro to nanometric length scales by high-resolution microscopy, indentation, surface profiling, and image analysis techniques. These multiscale processing-microstructure-property correlations can usher a major advancement to metal matrix composite manufacturing. 

Ultrasonic Treatment Maps Correlations for Advancement of Metal Matrix Nanocomposite Manufacturing Technology

Mechanics of Scaffolds and Soft Materials for Engineering Cardiac Tissues

CELL-MET Engineering Research Center, a collaborative effort between Boston University, University of Michigan, FIU and several other partner institutes, is working on the ambitious goal of engineering cardiac patches to repair human heart damaged by heart attacks. The mechanical microenvironment plays an important role in the maturation and organization of the cells. Agarwal’s group at FIU brings its expertise on nanomechanics, biomechanics and in-situ mechanical characterization, vital for developing novel scaffolds and devices for engineering cardiac tissues from a patient’s own stem cells. A key focus of Agarwal’s group is to examine the mechanical properties and deformation mechanisms of micro-scaffolds printed by the two-photon polymerization technique. This is achieved by in-situ testing inside high-resolution electron microscope. The real-time insights are important to understand how different scaffold architectures respond to forces due to tissue contraction. Agarwal’s group works closely with chemists to probe the mechanical properties, such as stiffness and hardness, of novel photoresists for developing soft polymeric scaffolds. The mechanical feedback helps in material selection and scaffold design, so as to mimic the native tissue environment. We also collaborate with bioengineers to probe the effect of diseases on the mechanical properties of cardiac tissues. As a part of our outreach and education efforts, our lab hosts undergraduate students and high school teachers for research exposure and training.

Mechanical testing of a micro-lattice by in-situ SEM nanoindentation

In-situ stiffness measurement of PDMS pillar in a tissue micro-actuator device