There are many successful examples of memory alloys in aerospace applications. The huge antennas on artificial satellites can be made of memory alloys. Before launching the satellite, the parabolic antenna will be folded up and loaded into the satellite body, and after the rocket lifts off and sends the satellite to a predetermined orbit, it only needs to be warmed up, and the folded satellite antenna will naturally unfold due to the function of "memory" and restore the parabolic shape.
Memory alloys have a wide range of applications in the clinical medical field, such as artificial bones, bone fixation and pressurization devices, dental orthodontics, various types of intracavitary stents, embolizers, cardiac repair devices, thrombus filters, interventional guide wires and surgical sutures, etc. Memory alloys are playing an irreplaceable role in modern medical treatment.
Memory alloys are also closely related to our daily lives. Just take the spring made of memory alloy as an example, put this kind of spring in hot water, the length of the spring will immediately elongate, and then put it into cold water, it will immediately return to its original state. The use of shape memory alloy springs can control the water temperature of the bathroom plumbing, in the hot water temperature is too high through the "memory" function, adjust or close the water supply pipe to avoid scalding. Can also be made into fire alarm devices and electrical equipment security devices. When a fire occurs, the spring made of memory alloy deforms and starts the fire alarm device to achieve the purpose of alarm. The spring made of memory alloy can also be placed in the valve of the heater to maintain the temperature of the warm room, and when the temperature is too low or too high, the valve of the heater will be opened or closed automatically.
As an emerging class of functional materials, many new uses of memory alloys are constantly being developed, such as the use of memory alloys made of eyeglass frames, if accidentally touched and bent, as long as it is placed in hot water heating, you can restore the original shape. In the near future, the shell of a car can also be made of memory alloy. If you accidentally touch the flat, as long as the hairdryer plus heat can be restored to its original shape, both save money and effort, is really convenient.
1, large amount of bending, high plasticity
2, above the memory temperature to restore the previous shape.
The earliest discovered memory alloy seems to be 50% Ti + 50% Ni
Applications:
Shape memory alloys are widely used in many fields such as aerospace, machinery and electronics, biomedical, bridge construction, automotive industry and daily life because of their many excellent properties.