Multi-scale, multi-dimensional and multi-physical measurements of dynamic material properties
Junyu Huang1, Sen Chen2, Lei Lu1, Duan Fan2, Shengnian Luo1,*
EXTENDED ABSTRACT: Advanced materials experience extreme environments such as impact and penetration during service. Multi-scale and multi-dimensional characterization of dynamic deformation and damage of materials is the foundation of service safety assessment. However, dynamic deformation and damage span across multiple temporal and spatial scales, and couple multiple physical quantities (including microstructures), which pose great challenge to traditional diagnostics. Ultrafast X-ray diagnostics based on synchrotron sources, with excellent temporal and spatial resolutions, provides an unprecedented opportunity for such studies. In this report, a simultaneous, ultrafast and in-situ X-ray phase contrast imaging and diffraction platform is constructed for gas gun loading (Fig. 1a), for the first time, using the self-developed loading systems including miniature one- and two-stage light gas guns, high-precision X-ray detection systems and timing control systems. The platform can launch projectiles up to 5.0 km/s, carry out multi-mode loading including plate impact and penetration, and integrate Doppler pin system to measure the free-surface particle velocity history. Single-pulse X-ray measurements can be conducted upon loading. The time resolution for imaging/diffraction can reach 80 ps, the imaging spatial resolution, 4 μm, and the diffraction spatial resolution, lattice scale. Then, simultaneous measurements of multiple physical quantities can be achieved, including macroscopic mechanical parameters, mseoscopic deformation fields and microscopic lattice evolution. In addition, large-scale scattering and diffraction simulation programs are developed to interpret diffraction data. Finally, this advanced technique is applied successfully to three impact problems: the high-speed penetration of a carbon-fiber unidirectional plate (Fig. 1b); deformation twinning of single crystal Mg under plate impact (Fig. 1c); shock-induced phase transition dynamics of single crystal KCl.
Figure 1 Ultrafast, in-situ X-ray phase contrast imaging and diffraction platform (a), along with two application samples (b) and (c).
BIOGRAPHY: Junyu Huang, associate professor of the Southwest Jiaotong University. He obtained his PhD at 2016 from the University of Science & Technology of China. He has worked on the impact dynamics of heterogeneous materials for years, and published over 40 papers in SCI journals including Acta Mater., Carbon and Int. J. Plasticity. He has undertaken the general and youth projects of NSFC, the sub project of "Challenge Project", and the Science and Technology Program of Sichuan Province.