current location：
shape memory alloy
SMA (shape memory alloy) is composed of two or more kinds of metal elements. It has the shape memory effect (SME) of thermoelasticity, martensitic transformation and its reaction. Shape memory alloy is one of the good shape memory materials. So far, more than 50 alloys have been found to have shape memory effect. There are many successful examples in the field of aerospace applications. Giant antennas on satellites can be made of memory alloys. Before launching the satellite, the antenna is folded up and placed inside the satellite. After the rocket put the satellite into orbit, it only needs to warm up. The folded plate expands naturally due to its "memory" function, thus restoring the shape of the plate.
Shape memory alloy (SMA) has been widely used in clinical medicine, such as artificial bone, bone injury fixation pressure device, tooth adjustment device, various cavity, embolism, heart repair, thrombus filter, interventional guide wire and surgical suture, etc. Memory alloy plays an irreplaceable role in modern medicine. Memory alloys are as important as our daily lives.
Shape memory alloy has shape memory effect. Take the spring made of memory alloy as an example. If the spring is placed in the hot water immediately, the length of the spring will change. Shape memory alloy spring can be used to control the water temperature of bathroom water pipe: when the hot water temperature is too high, adjust or close the water supply pipe through the "memory" function to avoid scalding. It can also be made into fire alarm equipment and electrical equipment safety equipment. In case of fire, the spring made of memory alloy will deform and start the fire alarm device to achieve the purpose of alarm. You can also put the spring made of memory alloy into the heating valve to keep the temperature of the greenhouse. When the temperature is too low or too high, it will automatically open or close the heating valve. Shape memory effect of shape memory alloy is also widely used in various temperature sensor triggers.
Another important characteristic of shape memory alloy is pseudo elasticity (hyperelasticity), which is that shape memory alloy has greater deformation recovery ability than ordinary metal under external force. This property is widely used in medical and architectural shock absorption as well as in daily life. For example, the above artificial bone, bone injury fixation compression device, orthodontics department, etc. Frames made of shape memory alloys can withstand greater deformation than ordinary materials without damage (instead of being reheated and restored by shape memory effects).
報(bào)錯(cuò)
