Modeling Relaxation Processes in Metallic Glasses Using the Mechanical Model

• Main Authors: V. Sh. Sarkisov, P. Yu. Ter-Mikaelyan, I. V. Moskin
• Format: Article
• Language: Russian
• Published: MGTU im. N.È. Baumana 2016-01-01
• Series: Nauka i Obrazovanie
• Subjects: creep; strain relaxation; mechanical model; metallic glasses
• Online Access: http://technomag.edu.ru/jour/article/view/55

<p>Currently, there is a growing interest in finding the patterns of relaxation processes in metallic glasses under mechanical action at temperatures below that of glass-transition, which are a basis for approval of proposed theories to simulate relaxation processes in metallic glasses and implement their proactive behavior under various loading conditions.</p><p>It is known that with tensile metallic glasses in creep mode at constant stress under isothermal conditions below the glass-transition temperature and stress in the nondestructive stress action the total strain consists of the elastic strain, immediately growing after the load applied, and the plastic deformation, growing in time. A Maxwell mechanical model takes into account that these two components of strain exist, and it can be used to describe the strain of solids at a qualitative level. The two available components of the total strain of both elastic and plastic form the basis for the proposed theories to describe the relaxation processes in metallic glasses. Therefore, in this paper we consider the possibility to simulate relaxation processes in metallic glasses, including quantitative estimates, using the Maxwell mechanical model.</p><p>To solve this problem, in the mathematical description of the two-component mechanical model are introduced a dependence of viscosity on time, stress, activation energy, and temperature, as well as a provision of the activation energy being independent on the deformation modes when reaching the specified stress.</p><p>Based on the equations has been developed a technique that uses the experimental creep curves to determine the elastic modulus and the parameters included in the dependence of viscosity. Applicability of the developed technique is demonstrated by comparing the experimental creep curves of metallic glass Co57Fe5Ni10Si11B17 with the calculated creep curves of various histories. Based on the results obtained, the paper comes to conclusion that it is possible to use the Maxwell mechanical model to simulate the long-term relaxation processes in metallic glasses, provided that additional provisions and dependencies are introduced into mathematical description of model.</p>