Komsomolsk-na-Amure State Technical University, Komsomolsk-na-Amure, Russia:
O. V. Bashkov, Assistant Professor, Head of a Chair of Materials Science and Technology of New Materials, e-mail: bashkov_ov@mail.ru
A. A. Popkova, Post-Graduate Student
T. I. Bashkova, Assistant Professor of a Chair of Materials Science and Technology of New Materials

Institute of Strength Physics and Materials Science of Siberian Branch of Russian Academy of Sciences, Tomsk, Russia:

Yu. P. Sharkeev, Professor, Head of Laboratory of Nanostructured Biocomposites’ Physics

Our paper presents the results of studies of damage accumulation kinetics in the titanium alloy VT1-0 (ВТ1-0) by acoustic emission (AE) method. The alloy VT1-0 was subject to cyclic bending in different structural states. Various titanium structure was obtained by equal channel angular pressing. The microcrystalline structure 200–300 nm was obtained by multiple pressing. Ultrafine-grained structure with the grain size 1–2 m and macrocrystalline structure with the grain size 20–30 m were obtained from the submicrocrystalline titanium  byserial annealing. Tests of cyclic bending were carried out in a special device with an electromagnetic drive for a low noise level. Cyclic tests were carried out with the acoustic emission registration. Acoustic emission sensor was mounted on a fixed side of the specimen. It was found that the decrease in grain size leads to increased durability of VT1-0 alloy samples. When tested with a stress of 500 MPa, the durability of the samples were as follows: 25–35 thousand cycles for the macrocrystalline structure, 75–85 thousand cycles for the ultrafine-grained structure, 100–120 thousand cycles for the submicrocrystalline structure. Fatigue stages were identified by the nature of the accumulation of total AE. The identification of the stages was carried out using division of AE signals on the various types of sources (dislocations, micro- and macrocracks). The earliest (relatively on the overall durability) registration of the AE signals of the dislocation type was revealed for the samples with the macrocrystalline structure. This is due to the development of microplastic deformation of the annealed macrocrystalline structure. The grain size reduction leads to the later (relatively on the overall durability) registration of the AE signals. The most later registration of AE signals of the various types of sources was revealed for the samples with submicrocrystalline structure. This is caused by small values of the mean free path of dislocations and the cracks increments due to the partition of the structure of the titanium samples on the substructural elements.

1. Biocompatibility. Ed.: V. I. Sevastyanov. Moscow : Informatsionnyy tsentr VNII geosistem, 1999. 368 p.
2. Valiev R. Z., Aleksandrov I. V. Nanostructured materials, obtained by intense plastic deformation. Moscow : Logos, 2000. 272 p.
3. Valiev R. Z., Aleksandrov I. V. Bulk nanostructured metallic materials: obtaining, structure and properties. Moscow : Akademkniga, 2007. 398 p.
4. Valiev R. Z., Semenova I. P., Latysh V. V., Shcherbakov A. V., Yakushina E. B. Nanostructured titan for bomedical applications: new development and prospects of commercialization. Rossiyskie nanotekhnologii. 2008. Vol. 3, No. 9/10. pp. 80–89.
5. Ivanova V. S., Shanyavskiy A. A. Quantitative fractography. Fatigue crack. Chelyabinsk : Metallurgiya, 1988. 400 p.
6. Stephens R. I., Fatemi A., Stephens R. R., Fuchs H. O. Metal fatigue in engineering : 2^nd ed. Hoboken : John Wiley & Sons, Inc., 2001. 496 p.
7. Bashkov O. V., Panin S. V., Lyubutin P. S., Byakov A. V., Ramasubbu S. Staging of deformation of polycrystalline materials. Investigation using acoustic-emission and optic-television methods. Tomsk : Izdatelstvo natsionalnogo issledovatelskogo Tomskogo politekhnicheskogo universiteta, 2014. 301 p.
8. Hamstad M. A., Gallagher A. O., Gary J. A wavelet transform applied to acoustic emission signals: Part 1: Source identification. Journal of Acoustic Emission. 2002. Vol. 20. pp. 39–61.
9. Barsoum F., Suleman J., Korcak A., Hill E. Acoustic emission monitoring and fatigue life prediction in axially loaded notched steel specimens. Journal of Acoustic Emission. 2009. Vol. 27. pp. 40–63.
10. Sharkeev Yu. P., Kukareko V. A., Eroshenko A. Yu., Kopylov V. I., Bratchikov A. D. et al. Regularities of formation of submicrocrystalline structures in titanium, exposed to intensive plastic deformation according to various schemes. Fizicheskaya mezomekhanika. 2006. No. 9. pp. 129–132.
11. Bashkov O. V., Parfenov E. E., Bashkova T. I. A soft and hardware complex for recording and processing of acoustic emission signals and for location and identification of their sources. Pribory i tekhnika eksperimenta. 2010. No. 5. pp. 67–72.
12. Bashkov O. V., Panin S. V., Semashko N. A. et al. Identification of resources of acoustic emission during deformation and distruction of steel 12Kh18N10T. Zavodskaya laboratoriya. Diagnostika materialov. 2009. No. 10. pp. 51–57.
13. Bashkov O. V., Bashkova T. I., Popkova A. A. The use of acoustic emission for the construction of a generalized fatigue diagram of metals and alloys. Advances in Acoustic Emission Technology. 2015. Vol. 158. pp. 283–291. DOI: 10.1007/978-1-4939-1239-1_26
14. Krasilnikov V. A., Krylov V. V. Introduction in physical acoustics. Moscow : Nauka, 1984. 403 p.
15. Muravin G. B., Simkin Ya. V., Merman A. I. Identification of mechanism of destruction of materials by spectral analysis of acoustic emission signals. Defektoskopiya. 1989. No. 4. pp. 9–15.
16. Braginskiy A. P. Definition of defects by spectral characteristics of acoustic emission. Defektoskopiya. 1984. No. 1. pp. 47–55.
17. Braginskiy A. P., Medvedev B. M., Platkov A. I. Amplitude-frequency method of location of acoustic emission sources. Defektoskopiya. 1988. No. 8. pp. 58–65.
18. Lysak N. V., Skalskiy V. R., Sergienko O. N. About the methodology of acoustic-emission diagnostics of fissure formation. Tekhnicheskaya diagnostika i nerazrushayushchiy kontrol. 1991. No. 3. pp. 9–14.
19. Bashkov O. V., Bashkova T. I., Romashko R. V., Popkova A. A. Design of integrated diagram of aluminium alloys fatigue using acoustic emission method. Tsvetnye Metally. 2016. No. 4. pp. 58–64. DOI: 10.17580/tsm.2016.04.10
20. Hamstad M. A., Mukherjee A. K. The dependence of acoustic emission on strain rate in 7075-T6 aluminum. Experimental Mechanics. 1974. Vol. 14, No. 1. pp. 33–41. DOI: 10.1007/BF02324858
21. Chenglong Shi, Guoqing Wu, Aixue Sha, Huiren Jiang. Effect of microstructures on fatigue property of TC18 titanium alloy with equal strength. Procedia Engineering. 2012. Vol. 27. pp. 1209–1215.
22. Pavel Mazal, Frantisek Vlasic, Filip Hort. Results of utilization of loading frequency and continuous sampling of ae signal for detection of fatigue damage of AlMg alloys. The 10th International Conference of the Slovenian Society for Non-Destructive Testing “Application of Contemporary Non-Destructive Testing in Engineering”. September 1–3, 2009. Ljubljana, Slovenia. pp. 385–391.
23. Miinshiou H., Jiang L., Liaw P. K., Brooks C. R., Seeley R., Klarstrom D. L. Using acoustic emission in fatigue and fracture materials research. JOM. Vol. 50. 1998. p. 349.