The international research group of Japan, France, Britain and Russia, led by Associate Professor Norimasa Ozaki of the Graduate School of Engineering, Osaka University and Makina Yabashi, Group Director of RIKEN, has set up SACLA, a facility of the RIKEN Center for Radiological Sciences. Using this method, we succeeded for the first time in the world in observing at the atomic level how the material breaks at the atomic level during an ultra-high-speed collision of 5 km / s.
When an object flying at ultra-high speed collides with a material, a characteristic fracture phenomenon occurs, such as greater damage being seen on the surface opposite to the collision surface.It has been extremely difficult to directly see the dynamic material fracture caused by such ultrafast stress because of its extremely short time.
The methods used by the research group this time are the "power laser shock ultra-high pressure method" that generates ultra-high pressure by condensing and irradiating a substance with a power laser, and the X-ray free electron laser (X-ray free electron laser) that is an X-ray generator in an accelerator. XFEL) "X-ray diffraction imaging" by facility SACLA.As a result, we succeeded in directly observing the ultrafast fracture phenomenon at the atomic level with a time resolution of femtoseconds (10 / 15th power of XNUMX seconds).It was clarified that the rapid concentration of submicron-level cracks in the crystal structure of the material leads to fracture fracture peculiar to high-speed collision.
This method enables quantitative evaluation of mechanical mechanical properties such as fracture stress (force per unit area required for material fracture) as well as ultrafast atomic level observation of material fracture behavior when ultrafast stress is applied. ..It is expected that this will promote the improvement of safety and the development of advanced high yield strength materials for materials used in extreme environments such as space stations and aircraft.
Paper information:[Science Advances] Dynamic fracture of tantalum under extreme strength stress
