Analysis of Fracture Scale and Material Quality Monitoring with the Help of Acoustic Emission Measurements

Abstract

The results of a study of the mechanism and kinetics of metallic material fracture (dual phase steels, binary Zr-2,5Nb and multicomponental Zr-1,2Sn-1Nb-0,3Fe alloys, reinforced surface layers and protective coatings, multifilamentary Nb3Sn and Nb-Ti based superconductors and HTSC-based composition wires) are given. The quantity fracture analysis is based on measurements of acoustic impulse peak (maximum) amplitudes by non-resonance sensors for linear measurement of acoustic shifts and crack parameters measurement. The developed methods of absolute calibration of AE equipment were checked by testing various types of materials and crack parameter measurements in laps and fractures. The calibration dependencies for quantity measurements are shown. The possibilities of AE for quality analysis and for characterizing of materials in the process of various mechanical tests and in the process of pressure processing with the help of a developed experimental computerized AE system are demonstrated.

Analysis of crack resistance and quality of thin coatings by Acoustic Emission

“…For studying behavior of a film upon mechanical loading, application of highsensitivity methods is necessary; one of which is measurement of acoustic emission (AE). We have showed the opportunity of the deformation and fracture processes analysis of thin layers and coatings by AE-measurements earlier [7,8]. In the present work the technique of crack resistance estimation of oxide coats on cladding tubes is presented.…”

“…These processes were accompanied by AE -impulses registered by the piezoelectric transducer, fixed directly on the specimen. Further, by means of the special equipment [8] signals were transferred in a personal computer for the subsequent processing and allocation of AE informative parameters.…”

Monitoring of materials, processes, and technologies by measuring acoustic emission

“…The high sensitivity of the characteristics of acoustic radiation to the formation of internal defects makes the method of acoustic emission applicable under conditions of high production noises for control over the processes of pressure treatment of metal [17]. The high noise level of the production imposes strict conditions on the detecting equipment and the method of signal processing.…”

“…The high sensitivity of the method for measuring AE signals makes it applicable under conditions of production noises for controlling pressure treatment of metals, for example, drawing of composite superconductors based on intermetallic compounds (such as Nb3Sn) or Nb -Ti alloys containing up to 50,000 fibers in a bronze (copper) matrix [17]. The friction pair "wire-tool" in drawing is effectively controlled by the method of AE in a wide range of deformation rates.…”

Computer technologies in metal science

“…The mesorelief of the middle of a fracture in a "large" specimen allows us to make a judgement about the toughness of the material, although the microscopic elements of the relief (dimples) are indistinguishable in it. l. Filtration of objects with respect to the stretch ratio Z (the ratio of the perimeter to the square root of the area), Image Expert Pro 1.0 packet (N. G. Chursin and G. V. Panteleev); a composite material of aluminum plus silicon carbides (• 100): A ) original structure, stretch ratio Z = 5.49 + 0,09; B) particles and clusters with Z = 5.08 +_ 0.05; C) separated particle clusters with Z = 9.89 +_ 0.45. zirconium reactor alloys [13]. l. Filtration of objects with respect to the stretch ratio Z (the ratio of the perimeter to the square root of the area), Image Expert Pro 1.0 packet (N. G. Chursin and G. V. Panteleev); a composite material of aluminum plus silicon carbides (• 100): A ) original structure, stretch ratio Z = 5.49 + 0,09; B) particles and clusters with Z = 5.08 +_ 0.05; C) separated particle clusters with Z = 9.89 +_ 0.45. zirconium reactor alloys [13].…”