Nano-scaled diffusional or dislocation creep analysis of single-crystal ZnO

Single-crystal nanocastles of ZnO

As a result of switching the growth from hexagonal disks to nanorods/nanobelts, single-crystalline ‘nanocastles’ of ZnO have been synthesized. This new structure was constructed by two basic parts: a sheet-like hexagonal crystal base and vertical nanorods/nanobelts surrounding the base as the ‘walls’ of the castle. Moreover, for the first time, ZnO nanorods with a triangular and diamond cross-s...

Mechanical deformation of single-crystal ZnO

The deformation behavior of bulk ZnO single crystals is studied by a combination of spherical nanoindentation and atomic force microscopy. Results show that ZnO exhibits plastic deformation for relatively low loads ~*4–13 mN with an ;4.2 mm radius spherical indenter!. Interestingly, the elastic–plastic deformation transition threshold depends on the loading rate, with faster loading resulting, ...

Dislocation jamming and andrade creep.

We simulate the glide motion of an assembly of interacting dislocations under the action of an external shear stress and show that the associated plastic creep relaxation follows Andrade's law. Our results indicate that Andrade creep in plastically deforming crystals involves the correlated motion of dislocation structures near a dynamic transition separating a flowing from a jammed phase. Simu...

Creep and Stress Relaxation Anisotropy of a Single-Crystal Superalloy

Dislocation mechanisms of creep in Ni3Al

The compressive creep deforrn;~tiort microstructure of polycrystalline Ni3AI h:is been observed by transnlission electron microscopy (TEM). ( 1 1 I ) rind ( 110) slip systems have been identified in primary creep. Dissociatiort of edge superparti:~l pairs perpendicular to the slip plane (both { 11 1 ) and ( 110) ) is common in crept specimens. I'he formation of this superdislocation...