Shape-memory alloys are materials which acquire a prescribed form when heated up to the so-called transformation temperature, and their initial shapes are restored on cooling. Such alloys are being developed because they possess unique properties: shape restoration on heating, slope of the characteristic (displacement versus temperature), possibility of compression on heating, repeated operation, large shear deformations, large stresses developed, effective damping, sound absorption, plasticity, superelasticity, prolonged retention of the properties, the possibility of combining sensitive and executing elements, constructional simplicity [1--3].An experimental industrial technology for fabricating different geometric forms of shape-memory materials has been developed and assimilated: rods with diameters ranging from 8 to 230 mm, wires with diameters from 0.2 to 7 mm, tubes with diameters from 14 to 60 mm, sheets with thicknesses from 0.5 to 10 mm, and ribbons with thicknesses from 0.04 to 3 mm [4]. Materials with a different transformation temperature have been obtained: up to ......Applications of shape-memory alloys in nuclear power. The possible applications of shape-memory alloys in nuclear power include passive safety systems, connecting, packing, and sealing elements (thermocouplings) for pipes and electric drives, equipment for efficient repair and assembly of units of a nuclear power plant, thermomechanical drives and motors, dampers, flow rate regulators, thermodetectors, direct-action (self-operating) emergency systems, units and elements (compensators) in electrical transmission lines, electric contact devices, and others [5].A direct-action emergency shielding is being considered primarily for action on the reactivity of the core of a nuclear reactor and/or on the temperature of the coolant or a structural element. Some of the units which have been developed, for example, couplings, caps for pipes, self-sealing interlayers, and direct-acting emergency units (for reactivity and flow rate). have been introduced into an information system developed at the Special Office of Machine Design (Nizhnii Novgorod) "constructions with the shape-memory effect in nuclear power technology" [6].Peculiarities of the application of shape-memory alloys in nuclear power [7--8]. Equipment with shape-memory alloys must be designed for use at temperatures ranging from below 100~ to above 600~ The temperature change that actuates the equipment ranges from 5--10 to 40--50~The equipment must remain operable under neutron fluences of up to 102~ cm -2. Moreover, such equipment can be located in different surrounding media (in nitrogen or helium, prepared or distilled water, melted sodium or lead). Equipment for application in nuclear power is developed on the basis of its functional peculiarities: required number of cycles, purpose (sealing, connection of pipes and ducts, covering of a pipeline, action on a working unit, safety systems, unsealing of vessels, rupture of an electric circuit, and so on), the working medium, and so ...

No abstract

Abstract. It is analyzed why shape memory alloys (SMA), which could enhance reliability, safety, compactness and simplicity of technical objects are still used insufficiently. The reasons presented are as follows: lack of literature on SMA application and books on shape memory device (SMD) development; need of metallophysicist support; lack of calculation technique for high-speed SMD and representative information on heating, on influence of harmful factors. Some ways to accelerate the process of SMD implementation are proposed: application concepts; publication of explanatory dictionaries (tSMA Application>) or ((SMD)), engineering design techniques and design estimates; inter-company catalogue of standard SMD.

No abstract

No abstract