The electrical, thermal, and microstructural characteristics of Ti/Al/Ti/Au ~30 nm/100 nm/30 nm/30 nm! multilayer Ohmic contacts to n-GaN ~doping level 5310 cm) were studied. The lowest contact resistivity derived from the annealed contact was rS53.0310 V cm. The contacts were robust and showed high-thermal stability. X-ray diffraction and Auger electron spectroscopy studies were made to invest...

The effects of welding energy on the mechanical and microstructural characteristics of ultrasonic-welded pure copper plates were investigated. Complex dynamic recrystallization and grain growth occurred inside the weld zone during ultrasonic welding. At a low welding energy, a thin band of straight weld interfaces was observed and had an ultra-fine grain structure. With an increase in welding e...

Porous ceramic materials are currently used as volumetric sunlight absorbers in concentrating solar power systems. As the efficiency of thermodynamic cycles rapidly increases with the operating temperature, the favorable characteristics of so-called ultra-high temperature ceramics (UHTCs) can be successfully exploited in novel solar absorbers. The present work reports, for the first time to the...

The tensile properties of an alloy can be exploited if detrimental defects and imperfections of the casting are minimized and the microstructural characteristics are optimized through several strategies that involve die design, process management and metal treatments. This paper presents an analysis and comparison of the salient characteristics of the reference dies proposed in the literature, ...