A New Sensor for the Electrical Equipment Leakage Current

To achieve the accurate and non-contact detection of the electrical equipment leakage current at the millampere level, this paper presents a new single-turn cored clamp-type sensor named the Microcrystalline-alloy Rogowski coil. The creative construction technique of the new sensor remedies the disadvantage of the Rogowski coil with the structure of microcrystalline alloy core. The experimental test of the prototype was carried out to show the superior performance and the excellent practical value in the application of the faint current measurement.

Validation of Ti-6Al-4V Alloy Mechanical Behavior Models for Conditions of Impact Damage of Turbine Engine Fan Blade

The article describes a series of experiments and calculations for verification high-speed deformation behavior and fracture models for the titanium alloy Ti-6Al-4V. Samples made of the micro-and nanocrystalline structure alloy Ti-6Al-4V were ballistically damaged in conditions that meet a ballistic damage of real turbine engine fan blades. It is found that the behavior of the microcrystalline alloy is more accurately described by the Johnson-Cook model. In the case of nanocrystalline material the best fit is achieved by using the Cooper-Symonds model. The achieved models parameters are presented.

Mechanical Properties of Ti–6Al–4V Titanium Alloy with Submicrocrystalline Structure Produced by Multiaxial Forging

A comparative investigation of mechanical properties of Ti–6Al–4V titanium alloy with coarse-grained (400 m), microcrystalline (10 µm) and submicrocrystalline (0.4 µm) structures in the temperature range 20–500°C has been carried out. The submicrocrystalline structure was obtained by multiaxial isothermal forging. The alloys with the coarse-grained and microcrystalline structures were used in a heat-strengthened condition. The microstructure refinement increases both the strength and fatigue limit of the alloy at room temperature by about 20%. The strength of the submicrocrystalline alloy is higher than that of the microcrystalline alloy in the range 20 - 400°C. Long-term strength of the submicrocrystalline specimens below 300°C is also considerably higher than that of the other conditions. However, the creep strength of the submicrocrystalline alloy is slightly lower than that of the heat-strengthened microcrystalline alloy already at 250°C. The impact toughness in submicrocrystalline state is lower especially in the samples with introduced cracks. Additional surface modification of submicrocrystalline alloy by ion implantation gives a considerable increase in the fatigue limit. Advantages of practical application of submicrocrystalline titanium alloys produced by multiaxial isothermal forging have been evaluated.

High Strength Nickel-Chromium-Molybdenum Microcrystalline Alloy Via Rapid Solidification Technology (Rst)

ABSTRACTThere is a growing national need for development of new improved materials having superior corrosion resistance combined with high mechanical strength. This paper discusses the properties and corrosion behavior of a new nickel-chromium-molybdenum microcrystalline alloy made via rapid solidification powder process, making it suitable for potential applications in corrosive environments. The alloy, called Markomet 1119, has the following composition in weight percent:Bal Ni, 20.3Cr, 22.8Mo, 2.9Fe, 0.5B, 0.8C.This is prepared as rapidly solidified powder by the method of a melt-spinning-pulverization process. The powder is consoldated into rods by hot extrusion. The mechanical properties and corrosion tests carried out on Markomet 1119 are reported. The microstructural feature of the alloy as investigated by SEM is also reported.