Metal Alloys Defy the Deep Freeze, Staying Tough at -253°C

Metal alloys defy the deep freeze, staying tough at -253°C

Scientists have discovered a class of metal that can unexpectedly resist extreme cold using an unusual mechanism. Normally such temperatures would make similar materials brittle and vulnerable to breaking. The findings, published in Nature, point to new principles for designing materials for cryogenic environments.

Competing mechanisms toughen bcc binary and medium-entropy alloys at 20 K

Plastic deformation in body-centred cubic (bcc) metals and alloys is conventionally mediated by screw dislocations. Their temperature-sensitive motion is attributed to a steep rise in strength with decreasing temperature that constricts plastic zones at crack tips, leading to a ductile-to-brittle transition1. Here we evaluated the mechanical properties of group IV–V bcc refractory alloys with similar electronic structures at 20 K and found that …

Twins and a hidden phase keep niobium alloys tough at 20 kelvin

Niobium-titanium-based body-centred cubic alloys retain high strength and fracture toughness at 20 kelvin because temperature-insensitive twinning and an omega-phase transformation nucleate dislocations before brittle failure can occur.