RheoMan: a five-year, ERC-funded (Advanced Grant), project to model the rheology of the Earth's mantle

Mar 11, 2016 Watching dislocations gliding in olivine Results

A hundred years after A. Wegener proposed his theory of continental drift, the motion of the crystal defects responsible for underneath mantle flow can be watched in situ in a transmission electron microscope

 At low temperature, olivine is brittle and plasticity can usually only be reached under high confining pressure. However, the toughness of a material depends on the size of the critical defect it contains. Hence, very small samples can sustain much larger stresses than macroscopic samples before fracturing. He rewe use this property to enhance ductility of olivine at room temperature and study dislocation mobility in situ in a TEM.

 

 

In this study, we present in situ TEM uniaxial tensile experiments performed on submicrometer beams of olivine using the single-tilt PI 95TEM PicoIndenter from Hysitron Inc. and a special push-to-pull (PTP) device

 

 

Push-to-Pull Device | Hysitron, Inc.

 

 

 

 

Dislocations gliding in olivine at room T under a 1.1 GPa shear stress

 

H. Idrissi, C. Bollinger, F. Boioli, D. Schryvers & P. Cordier (2015) Low-temperature plasticity of olivine revisited with in situ TEM nanomechanical testing, Science Advances, 2, e1501671, doi: 10.1126/sciadv.1501671