Research
- Fatigue and Fracture of implantable multistrand silver cored cables and interconnects
- Ultrasonic Bonding of Amorphous Metal Foils
- US-Egypt Collaborative Grant - Processing and Mechanical Properties of Amorphous Metal Foil and Laminates
- Damage Tolerant Structural Amorphous Metals: Intrinsic and Extrinsic Approaches
- Fracture and Fatigue of Amorphous Aluminum Alloys
- Effects of Interfaces on Blast Resistance of Amorphous Metals
- Low Mass Aerospace Ball Bearing Retainer Development
- Ultra-high Temperature Refractory Alloys for Aerospace Applications
- High Performance Corrosion Resistant Coatings
- Fundamantal Approaches to Design of Tough Fe-based Metallic Glasses
- Materials Issues for Blast Mitigation
- Effects of Changes in Strain Rate and Test Temperature on Mechanical Behavior of HSLA-65 Steel Relevant to Friction Stir Welding Conditions
1. Fatigue and Fracture of implantable multistrand silver cored cables and interconnects
A team of materials scientists is supporting the development of Networked Implantable Neuroprostheses (NNPS) Systems on an NIH-Bioengineering Research Partnership with the Cleveland Functional Electrical Stimulation (FES) center. The Materials Group is leading the material and structural evaluation, analysis, and testing of implantable leadwires and interconnects that form part of the NNPS. Currently the potential use of silver cored Drawn Filled Tube (DFT) cables as leadwires is being investigated. The response of various configurations of the DFT cables to static and cyclic mechanical loading imposed during long-term implantation is being studied experimentally. Evaluation of mechanical integrity of interconnects that joins the leadwires with the various modules of the NNPS system is also currently underway.
 
Upper Extremity NNPS
Electrodes for NNPS
(Images coutesy: Cleveland FES center )
Tension and fatigue behavior of DFT cables with various configurations as shown below are under investigation
(Images coutesy: http://www.fortwaynemetals.com )
7x7 implantable cable tested in Flex tester
(Image coutesy: http://www.fortwaynemetals.com)
For more information:
2. Ultrasonic Bonding of Amorphous Metal Foils
Support: Boeing/DARPA
Ultra-lightweight amorphous metals are being bonded via a variety of ultrasonic techniques. The mechanical behavior of the amorphous metal foils are being determined both before and after bonding by using a variety of testing techniques including: Hot microhardness testing, tension testing, interface toughness measurements, interface strength measurements.
3. US-Egypt Collaborative Grant - Processing and Mechanical Properties of Amorphous Metal Foil and Laminates
Support: NSF International Collaborative Program
The effects of chemistry changes on the mechanical behavior of Fe-based metallic glasses are being determined in tension, bending, flex bending fatigue, and notched/precracked toughness. In addition, lamination studies are being conducted in order to improve the mechanical behavior of the Fe-based metallic glass materials.
4. Damage Tolerant Structural Amorphous Metals: Intrinsic and Extrinsic Approaches
Support: DARPA
The effects of INTRINSIC and EXTRINSIC approaches to improving the balance of mechanical properties in ultra-light weight bulk metallic glasses is being investigated. INTRINSIC approaches include changing the elastic constants via chemistry changes in order to produce more ductile/tough systems. EXTRINSIC approaches include compositing in order to produce more energy absorbing systems.
Intrinsic and Extrinsic toughening of BMGs
5. Fracture and Fatigue of Amorphous Aluminum Alloys
Support: Pratt & Whitney/DARPA
Deformation processing of amorphous aluminum alloy powders has been utilized to produce novel nanostructured aluminum composites. The effects of various processing conditions on the strength, toughness, and high cycle fatigue behavior is being determined at room temperature, 300F and 500F and compared to conventional aluminum alloys.
6. Effects of Interfaces on Blast Resistance of Amorphous Metals
Support: ONR
Description: The effects of interfaces on the energy absorbing characteristics of bulk metallic glasses are being determined. Both Zr-based and Fe-based bulk metallic glasses are being tested under quasi-static and high strain rate conditions via collaborations with Prof. Vikas Prakash in Mechanical and Aerospace Engineering at CWRU. Novel insert designs have been prepared for testing while ultra-high speed video (e.g. Up to 200,000,000 frames/sec) has been utilized to capture the deformation and fracture characteristics of these novel materials.
7.Low Mass Aerospace Ball Bearing Retainer Development
Support: TIMKEN/AFRL
The fracture and fatigue behavior of candidate bearing retainer materials are being evaluated over temperature ranges relevant to potential applications.
8. Ultra-high Temperature Refractory Alloys for Aerospace Applications
Support: GE
The fracture and fatigue behavior of advanced Nb alloys are being determined over a range of test temperatures. Both SEM and Laser Confocal Microscopy are being used to characterize the microstructures and crack paths selected under monotonic and cyclic loading conditions.
9. High Performance Corrosion Resistant Coatings
Support: DoE
HVOF coatings have been prepared using Fe-based bulk metallic glasses. The performance of the coatings as well as drop cast ingots of the Fe-based bulk metallic glass have been determined over a range of temperatures using hot hardness and compression testing in addition to fracture toughness measurements. The effects of thermal exposures on microstructure evolution and resulting properties have also been determined.
10. Fundamantal Approaches to Design of Tough Fe-based Metallic Glasses
Support: University of Virginia/ONR
Description: The effects of systematic changes in the chemistry of Fe-based bulk metallic glasses on the toughness is being investigated. Systematic changes to the chemistry are being performed in order to change the elastic constants in a manner more conducive to plastic flow and enhanced toughness.
11. Materials Issues for Blast Mitigation
Support: ONR
The effects of microstructural changes and thermal exposures on the energy absorbing ability of 5XXX aluminum alloys is being determined under quasi-static and high strain rate conditions. Microstructural changes are being documented using TEM on both annealed and service-exposed materials while fracture toughness and high strain rate studies are also being conducted in conjunction with Prof. Vikas Prakash, Mechanical and Aerospace Engineering Department, on both as-received and service-exposed materials.
12. Effects of Changes in Strain Rate and Test Temperature on Mechanical Behavior of HSLA-65 Steel Relevant to Friction Stir Welding Conditions
Support: ONR
The effects of changes in test temperature and strain rate on the flow stress of HSLA-65 relevant to friction stir welding conditions is being determined. Collaborative work with Prof. Vikas Prakash, Mechanical and Aerospace Engineering Department, is being conducted to devise experiments to probe the mechanical behavior of steels under conditions
relevant to friction stir welding conditions.
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