Crack formation captured in 3D in real time

The research could allow material scientists to develop stronger, more durable materials. The findings -- published Thursday in the journal Nature Communications -- could also help engineers identify structural weaknesses before disaster strikes.

The new 3D images showcase the growth of a tiny crack in metal caused by hydrogen.

"Hydrogen gets into the metal and causes it to fracture unexpectedly in a process called hydrogen embrittlement," said reactor engineer John P. Hanson.

Hanson lead the research into metal damage caused by hydrogen while earning his doctorate at the Massachusetts Institute of Technology.

In 2013, engineers found 32 of the 96 metal bolts vital to the integrity of San Francisco's famed Bay Bridge had been damaged by hydrogen embrittlement.

Despite decades of research, scientists have struggled to understand how hydrogen damages metal.

"We don't have a complete understanding of the mechanisms behind it," said Hanson.

The risk of hydrogen embrittlement forces engineers to reinforce bridges and other structures with failsafe features, making construction more expensive.

To better understand the problem of hydrogen damage in metal, scientists deployed two advanced imaging technologies, high-energy diffraction microscopy and X-ray absorption tomography. The 3D images captured using the novel technologies showed microscopic fractures in nickel superalloys travel along the boundaries between the metal's individual microscopic crystals, or grains.

Not all grain boundaries in nickel superalloys are the same, and researchers were able to identify which types of boundaries are more likely to propagate cracks and which are more likely to resist them.

"We were able to show not only which grain boundaries are stronger, but exactly what it is about them that improves their performance," Hanson said.

Scientists hope their work will inspire the development of stronger metals, but for now researchers say they can use their findings to identify metal components most at risk of structural failure.