In a recent experiment, researchers at Texas A&M and Rice University marched an engineered diamond composite directly into a firing line. Then, they blasted it with aluminum projectiles flying at nearly eight times the speed of sound. The target not only withstood the strike but also morphed under fire.

Within microseconds of impact, portions of the ultra-rigid diamond composite underwent an instant, atomic-scale metamorphosis, turning into graphite. This sudden phase transition let the target act as an immediate shock absorber, dispersing kinetic energy at the molecular level thanks to graphite’s softer carbon structure.

The study was spearheaded by doctoral candidate Aniket Mote and Dr. Thomas Lacy of Texas A&M, using a 45-foot two-stage light gas gun at the university’s Hypervelocity Impact Laboratory (HVIL). 

“We found that portions of the diamond composite had transformed into graphite,” Lacy said. “It was exciting to observe this phase change in real time.”

Understanding how hard materials change their internal structure under intense mechanical stress provides defense and aerospace engineers with a fresh blueprint for advanced design.

Extreme forces driving modern aerospace and defense systems expose structural materials to rapid deformation, crushing pressure, and sudden failure. 

Studying the diamond-to-graphite transformation gives a clear look at these rapid physical reactions during high-velocity impacts. Experiments replicating hypersonic stress records phase changes in real time. It reveals exactly how super-hard composites transition between atomic states under intense shock.

To forge the target in the first place, Rice University scientists bound small diamond grains with cubic boron nitride and cobalt using spark plasma sintering.

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