A5072467773- Shape Memory Alloy Transformations
- Titanium Alloys Microstructure and Properties
- Ferroelectric and Piezoelectric Materials
- Additive Manufacturing Materials and Processes
- Innovations in Concrete and Construction Materials
- Metal and Thin Film Mechanics
- Magnetic and transport properties of perovskites and related materials
- Elasticity and Wave Propagation
- Cellular and Composite Structures
- MXene and MAX Phase Materials
- Topology Optimization in Engineering
- High Entropy Alloys Studies
- Advanced Welding Techniques Analysis
- Microstructure and Mechanical Properties of Steels
- Laser Material Processing Techniques
- Intermetallics and Advanced Alloy Properties
Czech Academy of Sciences, Institute of Physics
2022-2024
Czech Academy of Sciences
2024
St Petersburg University
2015-2022
Constitutive behavior of engineering materials is typically characterized by stress–strain curves from isothermal tensile and/or compression tests until fracture. Strain reversible martensitically transforming shape memory alloys (SMA) additionally cyclic and strain-temperature limited to temperatures stresses, at which the recorded strain responses are in closed loop cycles. In this work focussing coupled martensitic transformation plastic deformation NiTi, we deformed nanocrystalline NiTi...
Although superelastic NiTi shape memory alloy wire displays very high resistance to plastic deformation in austenite and martensite phases, incremental strains are recorded whenever the cubic monoclinic martensitic transformation (MT) proceeds under external stress leading functional fatigue degradation. Therefore, special closed-loop thermomechanical loading tests were performed shed light on mechanism by which strain generated. These revealed that both forward reverse MTs occurring above...
A model accounting for the microstructure of porous TiNi shape memory alloy samples fabricated by self-propagating high temperature synthesis has been proposed simulation their functional-mechanical properties. Structural elements a sample have approximated curved beams. An analysis shapes and sizes pores ligaments permitted to identify characteristic mathematical object consisting rigidly connected small curve beams considered. The stress-strain state beam was estimated classical methods...
Abstract Compared to conventional engineering materials, NiTi shape memory alloys deform via a wide range of deformation mechanisms owing the B2⇔B19’ martensitic transformation, including twinning in martensite and plastic by dislocation slip. A detailed understanding functional properties requires comprehensive knowledge all processes possibly activated thermomechanical loads. stress-temperature diagram (Fig. 1c), constructed from results isothermal 1a) isostress 1b) tensile tests on...
Abstract The stress-strain-temperature thermomechanical responses of NiTi shape memory alloys due to B2-B19′ martensitic transformation (MT) should ideally be phase and strain reversible in closed-loop load cycles, where the austenite martensite phases do not undergo plastic deformation. However, this ideal behavior is only observed when MT occurs under zero or very low externally applied stresses. When higher stresses, it generates small strains. These strains accumulate whenever proceeds...
Functional behavior of NiTi shape memory alloys is restricted to temperatures below 150 {\deg}C. To shed light on the origin loss functional properties with increasing temperature, we have investigated stress induced martensitic transformations in nanocrystalline wire by thermomechanical testing supplemented post-mortem reconstruction martensite variant microstructures grains transmission electron microscopy. It was found that forward transformation proceeding via propagation macroscopic...
Superelastic NiTi 1 shape memory alloy (SMA) wire was subjected to thermomechanical loading tests in tension evaluate stress and temperature conditions under which the deforms plastically. Although demonstrated a very high resistance plastic deformation both austenite martensite phases, incremental strains were recorded whenever B2 cubic B19' monoclinic martensitic transformation (MT) took place external stress. To shed light on origin of functional fatigue presumably originating from...
A model for simulation of the mechanical properties porous NiTi shape memory alloy samples (SMA) with high through porosity has been proposed. Such are obtained from nickel and titanium powders by self-propagating high-temperature synthesis under specially selected technological conditions. The structure corresponds to a set ligaments without clearly defined orientation pore channels. In this work, study microphotographs 60 % carried out. Basing on such material approximated beam consisting...
The deformation behavior of porous shape memory alloy (SMA) is determined both by the features their inhomogeneous structure and martensitic transformation. present work shows results simulation aimed at clarifying influence these factors on SMA. structures samples with different orientations pore channels are approximated sets beams various configurations, constitutive relations microstructural model used for calculations strain associated transformations. performed a dense SMA sample,...