9403832 Vohra The central goal of this research is to investigate the stability of novel phases in technologically important metals and alloys subjected to extreme conditions of temperatures and pressures. This research is carried out at the High Pressure Laboratory at the University of Alabama at Birmingham and the National High Pressure Beam Lines at the CHESS and NSLS Synchrotron Facilities. Metals and alloy samples are studied at high pressure/high temperatures in diamond anvil cell devices and probed by x-ray diffraction and laser spectroscopic methods. The fundamental aspects are the profound changes in the bonding in metals by compression, and the technological potential is in retaining these new modifications at ambient conditions. The focus of this research is the prototype classes of metals and alloys with different initial bonding configurations. In f-electron systems, the focus is on the cerium- thorium alloy system. Here the motivation is to understand the f- delocalization under pressure in rare earths and actinide metals. In d-electron systems, the focus is on molybdenum-ruthenium and titanium-vanadium alloy systems to investigate phase transformations predicted from theoretical considerations and quenching novel phases at ambient conditions. Synthetic diamonds have shown great potential as anvils in diamond cell devices due to lack of stress induced fluorescence as compared to natural diamonds. Development of synthetic diamond anvil technology for high pressure/high temperature research is continued. The research facilities supported by this grant have been utilized in the past during the summer in the research projects for undergraduates in the Alliance for Minority Participation (AMP) program in Alabama. Training of undergraduate and graduate students in metallurgical transformations, synchrotron based research, and fundamental understanding of phase changes in metals and alloys continues to be the primary mission. %%% This grant e xplores metallurgy phase stability at high pressures and temperatures of potentially important technological materials. ***
