METHOD OF MECHANICAL PROPERTIES DETERMINATION OF MATERIALS WITH SHAPE MEMORY Russian patent published in 2017 - IPC G01N3/18 

FIELD: machine engineering.

SUBSTANCE: invention relates to the nondestructive testing of materials with shape memory effect and can be used to control mechanical characteristics in terms of passive deformation of materials with shape memory effect for determining and monitoring temperature points of phase transformation, thermal coefficient and elastic recovery, as well as for the control of shape memory alloys obtained by matching the specified thermal-mechanical characteristics, necessary to ensure the health of thermo-mechanical joints when assembled with the help of thermo-mechanical coupling of the alloy with shape memory effect. An annular sample from a shape memory material in an austenitic state with a thermocouple and a displacement sensor supplied to it, an external diameter of the sample ring, a vertical loading of the annular sample in the austenite state along its diameter, a measurement of elastic austenitic deformation, cooling Annular sample with a vertical load applied to it, simultaneously measuring the accumulated martensitic deformation until the transfer of the material with the memory effect of the shape of the annular sample is completed during the direct martensitic transformation into the martensitic state until a steady-state value of the accumulated martensitic deformation, determining the total strain by adding elastic austenite deformation and accumulated martensite deformation, heating ring sample with the enclosed vertical load with simultaneous measurement of thermomechanical reduced strain to complete the transition of the material with shape memory annular sample the reverse martensitic transformation in austenitic state until a steady-state value of thermomechanical reduced deformation withdrawal applied vertical load, and then, measuring the elastic recovery of deformation and permanent deformation, plotting deformation temperature, determining temperature beginning and end of the direct and inverse martensitic transformation, followed by determination of mean values of temperatures of direct and inverse martensitic transformation, the hysteresis value, the relative values elastic austenitic, martensitic accumulated, complete thermomechanical restored, the elastic recovery and the residual deformation and thermomechanical coefficients.

EFFECT: improvement of accuracy of thermo-mechanical characteristics through martensite shift towards vector current voltage in terms of passive deformation with getting large values of absolute deformations, implementing the reversibility of the process of form reconstruction, to obtain a full-cycle curve of the transition processes in the form of a hysteresis loop, retrieve all temperature phase transformation points.

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