High Strain-Rate Ductile to Brittle Transition in Nanoporous Zeolite

Synthetic nanoporous zeolite was investigated by nanoindentation at low strain-rates and laser-generated stress waves at high strain-rates. Under quasi-static conditions zeolite has enhanced ductility and resilience. Under high strain-rate conditions zeolite undergoes a ductile to brittle transition. Compressive, uniaxial strain loading was achieved with an acoustically matched windowing material to prevent tension in the zeolite. Stresses as low as 400 MPa resulted in multiple fractures not originating from a single flaw. Under tension the spallation strength of zeolite was measured as 215 MPa with transgranular fracture observed as the dominant spallation feature, further indicating the brittle failure at high strain-rates.