Fracture Mechanism Analysis of the Heat-Resistant Steel 15Kh2MFA(II) After Laser Shock-Wave Processing
- PDF / 1,768,251 Bytes
- 7 Pages / 595.276 x 790.866 pts Page_size
- 100 Downloads / 176 Views
TECHNICAL ARTICLE—PEER-REVIEWED
Fracture Mechanism Analysis of the Heat-Resistant Steel 15Kh2MFA(II) After Laser Shock-Wave Processing I. B. Okipnyi • P. O. Maruschak • V. I. Zakiev V. S. Mocharskyi
•
Submitted: 1 February 2014 / Published online: 10 September 2014 Ó ASM International 2014
Abstract The surface strengthening mechanisms of the 15Kh2MFA(II) heat-resistant steel are analyzed after the laser shock-wave treatment in the air and epoxy resin. The regularities are established in the formation of the ordered surface relief of the steel after treatment. The optical and digital analysis of the surface is performed which allows determining the size of irregularities, taking into account the stochastic and cyclic nature of their formation. The effect of treatment of the 15Kh2MFA(II) heat-resistant steel on the regularities of its static failure is established. Keywords Fracture Strain localisation Deformation relief Mesomechanics Laser shock wave Relief
Introduction It is known that the laser shock-wave treatment of steel allows modifying the material properties due to the introduction of the concentrated energy flows into the material [1]. In addition, the interaction takes place between the high-energy laser radiation and the agent, or the transparent condensed medium preliminarily applied to the surface, which induces an impact wave [2]. The self-ordered sur-
I. B. Okipnyi P. O. Maruschak (&) V. S. Mocharskyi Ternopil National Ivan Pul’uj Technical University, Ruska 56, Ternopil 46001, Ukraine e-mail: [email protected]; [email protected] V. I. Zakiev National Aviation University, Kosmonavta Komarova ave. 1, Kiev 03680, Ukraine
123
face relief appears [3–5]. This physical phenomenon is explained by the incompatibility of strains of the two interconnected media, which appears in the multilevel systems, i.e., on the ‘‘surface layer—material volume’’ interface [6]. The laser shock-wave treatment redistributes stress and strains in the material surface layer, thus enhancing its mechanical properties and crack growth resistance of the modified material [5]. However, an important aspect of the problem still remains the stochastic nature of failure processes of the laser-treated materials (spatial variation of the mechanisms and size effects) caused by the random distribution of point defects [7]. The technological possibilities of the laser shock-wave treatment are much greater than those of the traditional thermal treatment. They allow obtaining the enhanced surface properties without impairing the plasticity of the base. In a number of works, a concept of the self-organization of the morphostructural formations is used, and its characteristics are linked to the conditions of processing, i.e., the spatial orderliness of formation of the material relief [3, 5, 7]. Therefore, developing scientific approaches to the modification of the material surface condition is the basis for the creation of a new method for strengthening structural materials. The purpose of this work is to analyz
Data Loading...
