Crystal ‘staples’ enhance strength of novel alloy

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Building on their research into a promising mixed alloy, a team of researchers at Osaka University in Japan have made a new breakthrough by adding two further metals to generate a unique structure that shows exceptional performance. They report their breakthrough in a paper in Scientific Reports.

Transition metal disilicides are lightweight alloys with good high temperature resistance, ideally suited for ultrahigh-temperature applications. The Osaka team had previously combined two different transition metal disilicides – niobium disilicide and molybdenum disilicide – to form a microscopic structure with alternating layers of the different metal crystals. This ‘lamellar’ arrangement improved the alloy’s strength, but some problems remained because the strength was still low along the direction parallel to the two-phase interface.

Now, the team has added two new metals – chromium and iridium – to the alloy mixture to form a ‘cross-lamellar microstructure’. The new metals cause the growth of new crystals, which penetrate the crystal layer structure, similar to staples piercing a stack of paper. This effect prevents deformation parallel to the lamellar interface, considerably improving the mechanical performance of the alloy.

Metal alloys companies will be benefit from this technology when it is mature. Let’s keep close attention to it.