Development of a hardware-software system for the experimental study of the ferromagnetic groove carrying conductor surface
The paper presents the results of an experimental study of the ferromagnetic groove electromagnetic field based on a developed laboratory bench equipped with a hardware — software measuring system. A technique for determining the current density in the conductor cross-section by measuring the magnetic field induction when immersing two types of sensors (frameless fine measuring coil and Hall sensor of a digital millislotometer) has been implemented for various depths inside the groove. The use of a measuring coil as a sensor makes it possible to obtain the current density distribution over the conductor height through the procedure of integrating the voltage proportional to the EMF induced in the measuring coil using a LabVIEW environment-built in a digital integrator. Measurement of magnetic field induction by the Hall digital sensor at a laboratory bench provides the measuring coil verification and the reliability of the experimental study results determination. With the help of the hardware-software complex, a distribution of the current density and magnetic induction along the conductor height in the ferromagnetic groove is obtained at a laboratory bench. The results of an experimental investigation of the surface effect are compared with the results of calculating the alternating magnetic field of a conductor with a current in a ferromagnetic groove in the Elcut 5.6 program complex. The active and the inductive conductor resistance at the industrial frequency are determined.
Measurement of the energy of grain boundary geometrically-necessary dislocations in copper
Measurements of the stored energy of cold work and recrystallization temperature of polycrystalline copper of a variety of grain sizes as a function of strain have been performed and it has been shown that: (1) The increase of stored energy with increasing strain falls into three distinct regimes as noted previously. (2) The total stored energy can be divided into two components: the stored energy from statistically-stored dislocations, which increases with increasing strain, and the stored energy from geometrically-necessary dislocation which increases sharply to a strain of {approximately}10%, at which point it saturates. (3) The saturation value of the stored energy from geometrically-necessary dislocations is inversely proportional to the grain size.
Production of amorphous and nanocrystalline iron based coatings by electro-spark deposition process
Abstract An iron-based alloy electrode with a high glass-forming ability was deposited on an austenitic stainless steel substrate by electro spark deposition at a range of process parameters. Overall, six specimens were coated with different parameters. Field emission scanning electron microscopy (FESEM) microstructural studies and X-ray diffraction (XRD) were conducted on the coated samples. The results showed that the coating structure is amorphous at low total heat input values, but at high values of total heat input, an extremely fine-grained or likely nanocrystalline structure is obtained. Hardness of amorphous coating was measured to be 1300 Vickers, which is similar to the hardness of the same Fe48Cr18Mo7B16C4Nb7 amorphous alloy.