Scientists have discovered a new mechanism that can significantly increase the strength of metals and ceramics without deteriorating their electrical conductivity..
All metals have defects that often lead to undesirable properties such as brittleness or weakening. This prompted scientists to create various alloys or heavy mixtures of materials to make them more durable. But the side effect of amplification is the loss of electrical conductivity..
To tackle this problem, a team of researchers from the Universities of California and Vermont, together with experts from several national laboratories in the United States, began to study the fundamental ideas of material design related to the reduction of the size of structural elements and their bonding. Although they have helped create stronger alloys and ceramics for over 70 years, they stopped working when they reached nanoscale..
As a result, the researchers found that combining the two approaches allows one to use nanodefects for amplification internal structure.
Model of a nanocrystalline structure inside a silver grain. Impurities of copper atoms are green, and internal defects – long sloping stripes.
In practice, the team added some copper to the silver to control the behavior of the defects. Thus, scientists used defects to their advantage to strengthen the metal without reducing its electrical conductivity. Since the impurities of copper atoms accounted for less than 1% of the total amount of silver and pass along each interface, and not between them, they do not disrupt the movement of electrons.
The durability of the silver created in this way was 42% higher indicator the previous world record, and with an optimal ratio, the hardness of its heat-treated version can be even higher.
According to scientists, this approach is applicable to many other metals. In the future, a new class of materials will increase the efficiency of solar cells, reduce the weight of aircraft and make nuclear power plants safer..
Recently engineers have also invented foam metal that can be spliced without melting.
text: Ilya Bauer, photo: University of Vermont