Acquisition of Upgrades for Raman Spectroscope for Enhanced Speed, UV and Polarization Capabilities
Abstract
The Defense University Research Instrumentation Program (DURIP) is designed to improve the capabilities of U.S. Universities to conduct research and to educate scientists and engineers in selected technical areas of importance to national defense. DURIP funding provides for the acquisition of research equipment and instrumentation for this purpose. This proposal is for the purchase of Upgrades for Raman Spectroscope. The P.I., Professor Ghatu Suhash, of the University of Florida will use the equipment to augment and enhance research capabilities in the area of transitions in ceramic materials subjected to dynamic loading. The objective of the proposal is to acquire a high-resolution rapid scan Raman spectroscopy system along with polarization and UV spectroscopic capabilities as upgrades to the existing Raman spectrometer, which is primarily used to characterize the deformation behavior and residual stresses in ultrahard ceramics. The proposed equipment serves the core mission of educating and training future researchers and engineers with expertise in disciplines of interest to the DoD. Advanced structural ceramics such as boron carbide (B4C) and silicon carbide (SiC) are preferred materials for armor due their high hardness and high strength. However, B4C undergoes structural weakening during high pressure loading through a mechanism referred to as ÔamorphizationÕ, wherein the crystal structure collapses to form nanometer-sized amorphous bands. The formation of these bands degrades the performance of the ceramic. Therefore, an understanding of the mechanics of amorphization is essential to the development of amorphization-resistant boron carbide. One of the easiest ways to detect amorphization in boron carbide is to use Raman spectroscopy because the Raman spectrum of an affected region contains new peaks associated with amorphization compared to that of the virgin material. Using this technique, the size and shape of the amorphized zone formed beneath the impacted surface of a B4C plate is being analyzed. Scanning of each amorphized zone takes more than 2 months (around 200 hours of Raman probe time) with the point-by-point Ômap scanÕ option currently available in the instrument. The proposed upgrades to the Raman spectrometer can improve the scan rate by 700 times, enabling the completion of each scan in less than 10 minutes and thus significantly reducing labor, usage time, and cost. In addition, ceramic composites have complex microstructures and possess process-induced residual stresses. Raman spectroscopy is an ideal tool for quantifying the distribution of residual stresses at the microscale in various phases of ceramic composites and provides critical insights into the performance potential of these materials. Utilizing polarized Raman spectroscopy, one can identify the direction of residual stress with respect to the crystallographic orientation of the grain as well as polymorphs, and polytypes of B4C and SiC phases. Finally, UV Raman spectroscopy will be used to gain a fundamental understanding of the shock-induced failure behavior of thin ceramic films and biological materials such as gels, brain tissue, and surrogates. Raman spectroscopy is a powerful tool for the development of fundamental knowledge in understanding the behavior of advanced ceramics, thin films, and biological tissues. As a convenient and versatile technique for high-resolution stress analysis and material characterization, the proposed upgrades to the Raman spectrometer will facilitate the training of new generation of scientists and engineers with the necessary skills and knowledge required to face the materials science and engineering challenges of the 21st century.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2017
- Source ID
- W911NF1610180
Entities
People
- Ghatu Subhash
Organizations
- Army Contracting Command
- United States Army
- University of Florida