【Deep Coating Society Popular Science Knowledge】Superplastic metal

What is superplasticity? In more academic language, it means that the material has extremely abnormal plasticity under certain conditions and does not break or even does not produce necking
.
To put it in layman's terms, everyone has seen pulling "dragon beard noodles", right? The dough used to pull "dragon beard noodles" is a superplastic material
.

It is believed that metal that appears the surface is difficult to pull like dragon whisker noodles
.
But in 1920, a scientist named Rosenhein found that under certain conditions, when studying the physical properties of zinc-aluminum-copper ternary alloys, it showed a viscosity phenomenon like maltose
.
In this state, the metal can be elongated 10 times, 20 times, or even 100 times higher, without necking or breaking
.
However, metals do not automatically have superplasticity, they must be pretreated under certain temperature conditions, and metals are superplastic only if tiny equiaxed grains are obtained
.
When the superplastic metal is deformed, the speed cannot be too fast, and it cannot be like pulling the "dragon's whisker face", it can only be "slowly", otherwise the speed cannot be reached
.
Why do superplastic materials have to have small grains? This is because the grains of the material are small, its grain boundaries are many, and the atoms slip easily
.
There is essentially no microstrain inside the grain, so the deformation resistance is much
smaller.

It has been found that many metal materials have superplasticity, for example, there are more than 100 kinds of superplastic aluminum alloys, of which there are five important industrial aluminum alloys, including pure aluminum, aluminum-copper alloys, aluminum-magnesium alloys, aluminum-zinc-magnesium alloys and aluminum-lithium alloys
.
Some nickel alloys, titanium alloys, ferroalloys, and zinc alloys also have superplasticity
.

Superplastic metals and alloys are widely used
.
For example, superplastic aluminum alloys can be "blown into" into various complex shells like blowing glass products by gas blowing to replace traditional sheet metal parts
on aircraft.
It can also be widely used
in the instrumentation, computer and decoration industries.
Superplastic zinc alloy can be used by extrusion or air blowing method to produce parts with complex shapes and clear contours, such as cavity dies of rubber or plastic products, punching dies of thin steel plates, various pistols with convex ribs, knobs, seeker flywheels, microwave conductors and commemorative coins, air pressure relief products and other crafts and various instrument shells
.

Carbon steels in superplastic ferroalloys can be used in the automotive industry to manufacture complex body parts
.
Superplastic titanium alloys have broader prospects in the aviation industry and shipbuilding industry
.
The United States has used titanium alloys and intermetallic compounds to supershape engine parts
.
Japan uses superplastic technology to manufacture aluminum matrix composites for the production of pistons
for automobile engines.

China began to study superplastic technology in the 70s, and formed a superplastic scientific research team
in the early 80s.
They have achieved a number of internationally advanced scientific research results based on structural alloy materials commonly used in industry, such as strategic missile titanium alloy high-pressure seamless gas cylinders and tactical missile turbine
disks.
Today, superplastic technology has developed into a new discipline
involving metal materials, metal physics, metal plastic processing and composite materials, and even intermetallic compounds and ceramics.

Source: New Materials Research

Statement: This number is neutral to reprinting, sharing, statements, and opinions, the purpose is only for industry exchanges, and the copyright belongs to the original author
.
If copyright and intellectual property rights and other infringement issues are involved, please contact this backend to delete the content immediately
.

Gather the ordinary and build greatness together