INVESTIGATIONS OF INTERFACIAL MATERIALS DESIGN - THE EFFECT OF INTERFACE MICROSTRUCTURES IN ZRCR1.8CU0.3 MG ON MGH2 FORMATION AS A RESULT OF HYDROGEN INTERDIFFUSION/

Composite materials ZrCr1.8Cu0.3Mg were prepared by heat treatments at various temperatures, as a series for the investigation of interfacia l materials design. In these composite materials, Mg2Cu phases are for med along the host-Mg interfaces with a layer-like microstructure by h eat treatment at 773 K, while with an eutectic microstructure at 873 K . The MgH2 formation owing to an interdiffusion of hydrogen atoms from the host compound phase is confirmed from both in-situ thermal analys es under an argon atmosphere and in-situ measurements of temperature-c hangeable X-ray diffraction under a vacuum. Moreover, this interdiffus ion is found to be enhanced in the eutectic interface. Consequently, i nterphase boundaries of an Mg2Cu/Mg eutectic are deduced to act both a s a diffusion path for the hydrogen atoms from the host compound into the Mg phase, and as stable nucleation sites for MgH2.