Magnetic Field Sensor Matrix pra-0091

Full Title Magnetic Field Sensor Matrix Tech Area / Field

INF-SIG: Information and Communications / Sensors and Signal Processing

PHY-SSP: Physics / Solid State Physics

INS-DET: Instrumentation / Detection Devices

Brief Description of Technology The principle of building a magnetic field sensor based on reluctant anisotropy in thin ferromagnetic film has been developed. This principle will be used in producing a magnetic sensor matrix with sensitive elements with of the dimensions, 1 1  0.1 microns. The sensor matrix works with stability in the range of fields between 0.001 and 1000 a/sm. The number of sensitive elements may be up to 1024. The particularity of this sensor concerns the possibility of measuring two orthogonal components of a magnetic field without additional spatial movement (while magnetic field measuring sensor is immovable).

Legal Aspects An experimental sample of a sensor with 256 elements has been produced by mask technology. The magnetically sensitive elements measured 400 100  0.1 microns. It is necessary to use higher technology for producing sensors with elements of micron dimensions. There is no necessity to change the sensor design, however. Experimental sensors are successfully used for the visualization of magnetic field leakage and micron-sized defects in magnetic defectoscopy. The application for a patent for the design of the matrix-sensor has been approved in Russia.

Special Facilities in Use and Their Specifications None.

Scientific Papers V.E. Scherbinin, A.S. Shleenkov, "Multi-Element Transducer-Aided Magnetic Monitoring of Welded Seams,” Condition Monitoring and Diagnostic Technology, Vol. 2., No. 3, pp.91-95 (1992).

Effective control of metal materials structure pra-0092

Full Title Effective Control of Metal Materials Structure by Influence of Excess Pressure on the Mobility of a Crystal-Melt Interface Tech Area / Field

MAT-ALL: Materials / High Performance Metals and Alloys

MAN-MAT: Manufacturing Technology / Engineering Materials

PHY-STM: Physics / Structural Mechanics

Description of Technology For the past of five years we have been studying the effects of excess pressures on crystal-melt phase transformation in metals. It has been a newly-discovered phenomenon: the extreme decrease of structure defects density of crystals grown from a melt under excess pressure of an inert gas in a crystallizer chamber. It has been found that, under optimal pressure values (depending upon the crystallographic orientation and the advance rate of crystal-melt interface), the impurity content and the dislocation density in the single crystals decrease greatly (by one and two orders of magnitude, respectively).

Theoretical analysis of experimental results allows us to assume that crystal-melt interface is able to become supermobile at the phase transformation and determines the conditions of the disappearance of thermodynamic and kinetic barriers for the interface motion in a condensed system. [Abstracts of the Tenth International Conference on Crystal Growth. (San-Diego, CA, USA), p. A154, p. D139 (1992)]. Also documented are the effects of excess pressure on dendritic morphology, the kinetic growth of crystals and pressure impulses during solidification of the melt on the grain sizes in an ingot and the cast structure of metal alloys. [Fizika Metallov i Metallovedenie, V.75, pp. 96-102 (1993)]. The results obtained point to a conclusion that low excess pressure is a parameter that permits effective control of the melt solidification process.

In the Crystal Growth Laboratory IMF, new methods were developed regulating solute concentration and structure defects density in single crystals grown from a melt for the effective refinement of materials, the growth of a single crystal, the regulation of dendritic structure alloys, the intensification of crystallization centers nucleation and the decrease of grain sizes in an ingot.

Legal Aspects The experimental results of the use of the method of regulation of dendritic structure of monocrystals of alloys by application of excess pressure on the crystallizing melt was approved by US Laboratories; the report was included in a volume for perspective commercial customers. Patent applications have been approved in Russia for methods of effective control of metal materials structure by influence of excess pressure on the mobility of a crystal-melt interface.

Special Facilities in Use and Their Specifications None.

Scientific Papers V.O.Esin, "Supermobility of Crystal-Melt Interface," ICCG-10. Abstracts from the Tenth International Conference on Crystal Growth. (San-Diego, USA), A154 (1992).

V.O.Esin, A.S.Krivonosova, I.Zh.Sattybaev, T.G.Fedorova, "Extreme Decrease of the Dislocation Density of Al Crystals Grown from the Melt under Pressure," Ibid, D139.

V.O.Esin, A.S.Krivonosova, I.Zh.Sattybaev, T.G.Fedorova, "Effect of Low Excess Pressure Impulses during Melt Solidification on Aluminum Alloys Structure," The Physics of Metals and Metallography, Vol. 75, No. 5, pp. 531-535 (1993).

V.O.Esin, A.S.Krivonosova, I.Zh.Sattybaev, T.G.Fedorova, "Effect of Pressure on the Efficiency of Aluminum Refinement at the Directed Crystallization of Melt," Visokochistie Veschestva, No. 1, pp. 71-76 (1995).