The technology and equipment for determination of residual stresses in the welded structures, using electron speckle-interferometry combined with the hole-drilling method (ESPI-HD), have been described. A special new approach to the conventional method of speckle-interferometry to investigate the stress gradients over the test object surface has been added. The developed equipment has been applied for determination of residual stresses in the different structures: the gas-turbine rotor, the welded shell and the structural elements with the large grain size.

The results of magnetization studies of the magnetoelectric antiferromagnetic LiNiPO4 single crystal in a pulse magnetic field with geometrical configuration H c are presented. The investigations have shown that a breakdown of the AFM state of LiNiPO4 in the magnetic field occurs by several stages. Temperature dependences of critical field values in the range 1.4 K -21 K are obtained.PACS : 75.50.Ee, 75.30.Kz

The resistive measurements were made to study the magnetic field-induced antiferromagnetic (AF) -weak ferromagnetic (WF) transition in La2CuO4 single-crystal. The magnetic field (DC or pulsed) was applied normally to the CuO2 layers. The transition manifested itself in a drastic decrease of the resistance in critical fields of 5-7 T. The study is the first to display the effect of the AF -WF transition on the conductivity of the La2CuO4 single-crystal in the parallel -to -CuO2 layers direction. The results provide support for the 3-dimensional nature of the hopping conduction of this layered oxide.

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Abstract. An electrode system for inducing a high density pulsed electric current (PEC) into the material for residual stresses (RS) relaxation has been proposed. A new non-destructive technology for determination of RS using electron speckle interferometry in combination with a local PEC treatment has been developed. Application of PEC at increased power parameters was investigated for control of stressed state of welded structures used in aircraft engineering. Results of practical application of the developed technologies and equipment are presented.