The progress of mankind is achieved through continuous exploration. Before our industry was underdeveloped, the choice of industrial raw materials was very scarce. We can only choose the raw materials that we can produce and use, but we can't choose which material we want to use. However, with the continuous progress of scientific exploration, people's progress and breakthroughs in raw materials are also increasing. A material called memory alloy has attracted people's attention. Next, let's learn about this memory alloy together.

Materials:

/kloc-in the 1970s of 0/9, an alloy with "memory" shape function appeared in the world material science. Memory alloy is a special kind of metal belt, which is easy to bend. We put it in a glass jar filled with hot water, and the metal strip rushed forward. Put it in cold water and the metal strip will recover. In a glass jar filled with cold water, stretch a spring, and when the spring is put into hot water, it automatically closes again. In cold water, the spring returns to its original state, but in hot water, it will contract. The spring can stretch and contract infinitely, and then contract and open. These are all made of a kind of intelligent metal with memory. Its microstructure has two relatively stable states. At high temperature, this alloy can be changed into any shape you want. At a lower temperature, the alloy can be stretched, but if it is reheated, it will remember its original shape and change back. This material is called memory metal. It is mainly made of nickel-titanium alloy. For example, a spiral superalloy is in a spiral state after high temperature annealing. At room temperature, it is forcibly straightened with great strength, but as long as NiTi memory alloy wire heats it to a certain "abnormal temperature", the alloy seems to remember something and immediately returns to its original spiral shape.

Alloy spring:

The spring is made of TiNi memory alloy wire, and the one-way memory effect of shape memory alloy is utilized. After stretching, with the increase of temperature, the temperature-sensitive driving element can recover its original length by itself. This kind of spring is also a typical structural form of industrial shape memory alloy elements. After stretching, hot water or hot air is used as the heat source, and the original length is 65℃-85℃, and the original length is 80 mm The martensite phase (i.e. phase structure at low temperature, where low temperature refers to room temperature) of the shape memory alloy is a soft phase, and the parent phase (i.e. phase structure at high temperature, where high temperature refers to 65℃-85℃) is a hard phase.

Use:

Memory alloys are widely used. For example, mechanical fastening pins and pipe joints, welding of fire alarms, connectors and integrated circuits on electronic instruments and equipment, artificial heart valves, massage sticks, cranioplasty, orthodontics and jaw restoration in medical treatment, etc. It will also play a magical role in communication satellites, color TVs, thermostats and toys, and will also become a new material memory alloy in modern navigation, aviation, aerospace, transportation, textiles and other fronts. It has been used in pipeline combination and automatic control. The casing made of memory alloy can replace welding by expanding the inside of the pipe end at low temperature. 4%, when assembled, the sleeves are sleeved together. Once heated, the sleeve contracts and returns to its original shape, forming a tight bond. There are 6,543,800 such joints used in the hydraulic system of American Navy aircraft, and there has been no oil leakage or damage for many years. It is very convenient to repair damaged pipelines of ships and submarine oil fields with memory alloy fittings. In some inconvenient parts, the pin is made of memory alloy, put into the hole and heated, and the tail automatically curls separately to form a single-sided assembly.

The application of memory alloy in medical treatment is also very eye-catching. For example, the bone plate used for fracture can not only fix two broken bones, but also produce compressive force in the process of restoring to the original state, forcing the broken bones to join together. Dental orthodontic wires, long clips for ligating cerebral aneurysms and vas deferens, and stents for straightening the spine are all started by body temperature after being implanted in the human body. Thrombotic filter is also a new product of memory alloy. After the straightened filter is implanted into the vein, it will gradually return to a mesh, thus preventing? 95% of blood clots flow to the heart and lungs.

Above, we introduced some knowledge about memory alloys. Firstly, we introduce the material composition of memory alloy. We all know that memory alloy can bend and deform in hot water, but it will straighten in cold water, which is caused by the different materials of memory alloy. Next, we introduce the spring made of memory alloy, which integrates the characteristics of memory alloy. Finally, we introduce the application of memory alloy. You can learn more about memory alloys from this article.