Scientists create lightweight, super-strong gold by drilling holes into it

Chinese scientists have presented a novel method for producing pure gold that combines light weight with remarkable strength.

This innovative approach, developed by researchers at the Shenyang National Laboratory for Materials Science, creates uniformly small pores in the solid metal.

The impact of this research could have significant implications for the aerospace, automotive and consumer electronics industries, where there is an urgent need for materials that are both robust and lightweight.

The science behind the innovation

Traditionally, metal forming techniques such as casting, welding and 3D printing are designed to eliminate internal bubbles in metals, as these are generally considered significant material defects.

Engineers have always been careful to avoid these voids because of their damaging effects. Internal bubbles can compromise the strength of the metal, reduce durability at joints, and degrade surface finish.

However, the research team led by Jin Haijun from the Chinese Academy of Sciences (CAS) has changed this perspective. Instead of eliminating the cavities, they have refined their size and regulated their shape and distribution.

The researchers found that this approach mitigates the negative effects of bubbles and can also provide unexpected benefits.

“This suggests an attractive opportunity to manipulate the properties of solids,” said Brent Grocholski, senior editor at Sciencereported by South China Morning Post.

The research shows how the traditional view that bubbles represent defects can be rethought to unlock new material capabilities.

Significant increase in strength through nanopores

The team used gold as a model material to develop their technique, creating uniformly structured porous gold through a dealloying corrosion process. By compressing and then annealing the metal – heating and cooling it – the researchers created a new material with scattered nanopores smaller than 100 nanometers.

Tests showed that adding nanopores at a volume fraction of 5 to 10 percent increased the strength of the gold by 50 to 100 percent. This improved material can support higher loads while retaining good plasticity. In some cases, the plasticity even exceeded that of fully dense gold of the same size.

“This improvement is due to the fact that the distributed nanopores help reduce the stress and strain concentration around the voids, thereby preventing the formation of cracks,” explained Jin Haijun.

“The large specific surface area of ​​the material facilitates interactions between the surface and dislocations, which improves strength and hardening rates, the latter contributing to improved plasticity,” Jin added. The strategic placement of these nanopores helps balance the strength and ductility of the material.

Impact on the environment and industry

The subtractive approach contrasts with traditional methods that increase strength by adding lighter alloying elements such as aluminum or lithium. The new method offers an environmentally friendly and cost-effective strategy for improving metals without adding weight or pollution. The scattered nanovoids reduce the density of pure gold by more than 10 percent, contributing to its lightness and recyclability.

This innovative approach also preserves the essential physical and chemical properties of gold, including its thermal and electrical conductivity and corrosion resistance.

“Gold with nanopores can be used, for example, as an interconnect or contact material in electronics,” Jin noted.

“This reinforcement strategy could also be applied to other metals and engineering alloys as long as the nanopores can be effectively integrated into the material, with potential applications in numerous fields,” concluded Jin.

The results were published in the journal Science.