Actual Problems in Machine Building 2015 No. 2

Актуальные проблемы в машиностроении. 2015. №2 Материаловедение в машиностроении ____________________________________________________________________ 369 FRACTOGRAPHY OF FATIGUE FAILURE OF THE SILUMIN SURFACE SUBJECTED TO ELECTRON-BEAM PROCESSING Gromov V.E. 1 , D.Sc. (Physics and Mathematics), Professor, e-mail: gromov@physics.sibsiu.ru Alsaraeva K.V. 1 , Ph.D. student, e-mail: alsaraeva_kv@physics.sibsiu.ru Ivanov Yu.F. 2 , D.Sc. (Physics and Mathematics), Professor, e-mail: yufi55@mail.ru Konovalov S.V. 1 , D.Sc. (Engineering), Associate Professor, e-mail: konovalov@physics.sibsiu.ru 1 Siberian State Industrial University, 42 Kirov Street, Novokuznetsk, 654007, Russian Federation 2 Institute of High Current Electronics, Siberian Branch, Russian Academy of Sciences, 2/3 Prospect Akademicheskii, Tomsk, 634055, Russian Federation Abstract Aluminium –silicon alloys having high specific mechanical properties are brittle and difficult-to- deform materials. It is necessary to essentially improve their structure and plastic properties to expand the areas of industrial application of these alloys. Material treatment by a high-intensity pulsed electron beam is an efficient method to modify a part surface and to increase their fatigue life. In this study the eutectic silumin surface was modified by a high-intensity pulsed electron beam. Also, the regularities of the formation of the structure and phase composition of silumin subjected to high-cycle fatigue tests up to failure were established by methods of modern physical materials science. Analysis of the surface layer structure revealed the sources of submicrocrack nucleation. It was also revealed that large silicon plates located on the surface and in the subsurface layer were the most dangerous stress concentrators. An irradiation mode increasing the silumin fatigue service life by over 3.5 times was discovered. It was found that a significant increase in the silumin fatigue life was caused by the formation of a multi-modal, multi-phase, submicro-and nano- sized structure. Keywords structure, silumin, electron beam treatment, fatigue service life, fractography of failure surface