Jet engines demand materials that can survive extreme heat and force without bending, cracking, or slowly losing shape. The strongest candidates, however, often come with a major weakness: they are too brittle to deform safely. Now, engineers at Purdue University have found a way to overcome that tradeoff in cobalt-aluminum (CoAl), an intermetallic compound with potential uses in high-performance turbines.
By redesigning the material at the nanoscale, the team created a form of CoAl that is exceptionally strong but can still undergo substantial deformation at room temperature. The key innovation lies in deliberately introducing controlled imperfections — crystal dislocations — that allow layers of atoms to slide past one another rather than fracture. In micropillar compression tests, the material achieved a yield strength exceeding 6 GPa and sustained work hardening to approximately 8.5 GPa, with compressive plastic strain exceeding 15%.
Intermetallics like CoAl contain two or more metallic elements arranged in a highly ordered crystal structure. This atomic order gives them remarkable strength, high melting temperatures, and resistance to creep — the slow deformation that occurs under long-term stress. But the same ordered structure typically prevents them from deforming easily, making them fracture under load instead of bending. The Purdue team used magnetron sputtering deposition to build the alloy as alternating nanoscale layers, creating flexible amorphous interfaces that unlock plasticity without sacrificing strength.
The advance, published in Science Advances, points toward a broader strategy for making notoriously brittle intermetallic compounds practical for aerospace engines, gas turbines, and defense technologies. Next-generation turbine blades made from this alloy could spin faster while sustaining higher centrifugal forces, dramatically improving engine performance and fuel efficiency.