Talant Ryspaev - Academia.edu (original) (raw)

Papers by Talant Ryspaev

Low density of magnesium alloys and relatively high specific strength are the main advantages of ... more Low density of magnesium alloys and relatively high specific strength are the main advantages of these materials. Magnesium alloys and composites are used in different industrial applications. As magnesium is recyclable, its extensive usage can minimize the negative impact on the environment due to non-degradable plastic wastes. Magnesium materials have low ductility at ambient temperature. This is a consequence of the hexagonal close-packed (hcp) crystal structure with a limited number of operative slip systems. The plasticity of magnesium alloys and composites increases at elevated temperatures where additional slip systems become active. However, low ductility of magnesium alloys prevents their application hence; the enhanced ductility of magnesium materials is of a special interest [1–4]. It is known that the fine grain size (d 10 μm) stable at higher temperatures is a main structural requirement for the occurrence of superplasticity. All characteristics of superplasticity (rela...

The article discusses the creation of geographic information systems (GIS), which allow you to qu... more The article discusses the creation of geographic information systems (GIS), which allow you to quickly and in detail analyze various alternatives based on the available geographically-related information for assessing the consequences of plant design options in a given wind power industry with the goals of ensuring sustainable development of the region. This mainly relates to energy facilities and systems that use wind energy sources, with their high spatial and temporal irregularity and variability. In accordance with the tasks that determine the necessary design parameters, the requirements for the initial physical-geographical, climatic, metrological, wind energy resources and energy-ecological potential information necessary for creating a GIS database arise. Estimates of wind energy and its distribution over the territory is hampered by the limited amount of energy potential in time and space. With the help of GIS, energy, economic, environmental, social issues and climate chan...

Communications - Scientific letters of the University of Zilina

Materials Science Forum, 2016

The grain refinement after thermo-mechanical treatment (TMT) was investigated in AZ91, AE42, und ... more The grain refinement after thermo-mechanical treatment (TMT) was investigated in AZ91, AE42, und QE22 magnesium alloys. The optimal over-aging temperature was determined to be 300 °C in the case of AZ91 and AE42 alloys and 350 °C for QE22 alloy. After optimized TMT, the average grain sizes were 13.5 µm (AE42), 11.1 µm (AZ91) and 1.9 µm (QE22). The QE22 alloy exhibited the superior superplastic properties, with maximum elongation to failure 750 % and strain rate sensitivity parameter m=0.73. The Friction Stir Welding showed that the original base material grain structure of the alloys AZ31 and AZ91 replaced by ultrafine grains in the stir zone. The purpose of the present paper is to present the results of the grain refinement in magnesium alloys by thermo mechanical treatment and stir welding.

Materials Science Forum - MATER SCI FORUM, 2008

The superplastic deformation characteristics of the AZ91, the mostly used magnesium alloy, were i... more The superplastic deformation characteristics of the AZ91, the mostly used magnesium alloy, were investigated at various strain rates in the interval from 3x10-5 to 1x10-2 s-1 and temperature of 420 °C. To prepare superplastic alloys thermo-mechanical treatment was used. Cast materials were heat-treated in two stages, after homogenization at 415 °C for 10 h were submitted to the precipitation annealing at temperature in the range of 200-380 °C for 10 h, and deformed by hot extrusion. Microstructure of samples was observed by the light microscope Olympus. Strain rate sensitivity parameter m has been estimated by the abrupt strain rate changes method. The strong strain rate dependence of the m-parameter was found. The highest elongation to failure, 584%, was found for the samples aged at 380 °C. Possible physical mechanisms of the superplastic flow are discussed.

Low density of magnesium alloys and relatively high specific strength are the main advantages of ... more Low density of magnesium alloys and relatively high specific strength are the main advantages of these materials. Magnesium alloys and composites are used in different industrial applications. As magnesium is recyclable, its extensive usage can minimize the negative impact on the environment due to non-degradable plastic wastes. Magnesium materials have low ductility at ambient temperature. This is a consequence of the hexagonal close-packed (hcp) crystal structure with a limited number of operative slip systems. The plasticity of magnesium alloys and composites increases at elevated temperatures where additional slip systems become active. However, low ductility of magnesium alloys prevents their application hence; the enhanced ductility of magnesium materials is of a special interest [1–4]. It is known that the fine grain size (d 10 μm) stable at higher temperatures is a main structural requirement for the occurrence of superplasticity. All characteristics of superplasticity (rela...

The article discusses the creation of geographic information systems (GIS), which allow you to qu... more The article discusses the creation of geographic information systems (GIS), which allow you to quickly and in detail analyze various alternatives based on the available geographically-related information for assessing the consequences of plant design options in a given wind power industry with the goals of ensuring sustainable development of the region. This mainly relates to energy facilities and systems that use wind energy sources, with their high spatial and temporal irregularity and variability. In accordance with the tasks that determine the necessary design parameters, the requirements for the initial physical-geographical, climatic, metrological, wind energy resources and energy-ecological potential information necessary for creating a GIS database arise. Estimates of wind energy and its distribution over the territory is hampered by the limited amount of energy potential in time and space. With the help of GIS, energy, economic, environmental, social issues and climate chan...

Communications - Scientific letters of the University of Zilina

Materials Science Forum, 2016

The grain refinement after thermo-mechanical treatment (TMT) was investigated in AZ91, AE42, und ... more The grain refinement after thermo-mechanical treatment (TMT) was investigated in AZ91, AE42, und QE22 magnesium alloys. The optimal over-aging temperature was determined to be 300 °C in the case of AZ91 and AE42 alloys and 350 °C for QE22 alloy. After optimized TMT, the average grain sizes were 13.5 µm (AE42), 11.1 µm (AZ91) and 1.9 µm (QE22). The QE22 alloy exhibited the superior superplastic properties, with maximum elongation to failure 750 % and strain rate sensitivity parameter m=0.73. The Friction Stir Welding showed that the original base material grain structure of the alloys AZ31 and AZ91 replaced by ultrafine grains in the stir zone. The purpose of the present paper is to present the results of the grain refinement in magnesium alloys by thermo mechanical treatment and stir welding.

Materials Science Forum - MATER SCI FORUM, 2008

The superplastic deformation characteristics of the AZ91, the mostly used magnesium alloy, were i... more The superplastic deformation characteristics of the AZ91, the mostly used magnesium alloy, were investigated at various strain rates in the interval from 3x10-5 to 1x10-2 s-1 and temperature of 420 °C. To prepare superplastic alloys thermo-mechanical treatment was used. Cast materials were heat-treated in two stages, after homogenization at 415 °C for 10 h were submitted to the precipitation annealing at temperature in the range of 200-380 °C for 10 h, and deformed by hot extrusion. Microstructure of samples was observed by the light microscope Olympus. Strain rate sensitivity parameter m has been estimated by the abrupt strain rate changes method. The strong strain rate dependence of the m-parameter was found. The highest elongation to failure, 584%, was found for the samples aged at 380 °C. Possible physical mechanisms of the superplastic flow are discussed.