Crystal ‘fault lines’ triple strength of magnesium alloy

Researchers from North Carolina State University have developed a new technique for creating stronger, lightweight magnesium alloys that have potential structural applications in the automobile and aerospace industries.

They achieved this by strengthening magnesium alloys with so-called nano-spaced stacking faults.

According to the university, these are essentially a series of parallel fault-lines in the crystalline structure of the alloy that isolate any defects in that structure. This increases the overall strength of the material by approximately 200 per cent.

‘This material is not as strong as steel, but it is so much lighter that its specific strength is actually much higher,’ said Dr Suveen Mathaudhu, a co-author of a paper on the research and an adjunct assistant professor of materials science and engineering at NC State under the US Army Research Office’s Staff Research Program. ‘In theory, you could use twice as much of the magnesium alloy and still be half the weight of steel. This has real potential for replacing steel or other materials in some applications, particularly in the transportation industry – such as the framework or panels of vehicles.’

The researchers were able to introduce the nano-spaced stacking faults to the alloy using conventional hot rolling technology widely used by industry.

‘We selected an alloy of magnesium, gadolinium, yttrium, silver and zirconium because we thought we could introduce the faults to that specific alloy using hot rolling,’ said Dr Yuntian Zhu, a professor of materials science and engineering at NC State and co-author of a paper on the research. ‘And we were proven right.’

‘Because we used existing technology, industry could adopt this technique quickly and without investing in new infrastructure,’ Mathaudhu added in a statement.

The paper, ‘Ultrastrong Mg-Alloy via Nano-Spaced Stacking Faults,’ was published online March 12 in Materials Research Letters.