![]() This condition is achievable at modern X-ray synchrotron sources that are already able to achieve a coherence volume of the order of several cubic micrometres 8.īCDI methods have been applied in a large variety of experimental settings. Both forward-scattering and Bragg scattering techniques require the coherence length of the incident X-ray wave to be larger than the sample size. BCDI is a Bragg scattering variant of the forward-scattering approach of Coherent Diffractive Imaging (CDI) implemented by Miao et al. ![]() It should be noted that the micro twins only form in the SC system due to the specific orientation and small cross sectional area of the SC system.Bragg Coherent Diffraction Imaging (BCDI) 1, 2, 3 by crystalline matter allows one to solve classical crystallographic inverse problems of phase retrieval using oversampling of experimental data 4, 5 and iterative reconstruction algorithms (see e.g., ref. At 14 GPa, micro twin faults (i.e., thin twin faults with only 3–4 atomic layers) form along the \((111)\) slip plane. From 0 to 10 GPa, this centerpiece goes through elastic deformation. ![]() The structure goes through the following stages. Figure 2 shows a series of snapshots of a centerpiece from the SC structure under ramp loading NEMD simulation at different timesteps. In this paper, all data shown will be from systems with the same dimensionless strain rate as the experiment in reference 11. The readers can refer to the Supplementary materials for a more detailed discussion on the fundamentals of the scaling method and NEMD simulation results under different dimensionless strain rates. Under this situation, the scaled setting will approach the shock regime, where the structure will exhibit different stress-density response compared to the shockless ramp loading experiment, shown in Fig. This is especially obvious when the dimensionless strain rate is larger than a certain threshold, i.e., temporal scaling factor being too large or spatial scaling factor being too small. When the dimensionless strain rate is different, the behavior of the system will start to deviate from the experiment. When a simulated system adopts the same temporal and spatial scaling factors as the experiment, its dimensionless strain rate will be the same as the experiment, and it serves as a good scaled representation of the experiment setup. The angle \(\chi\), which is the angle between the sample norm and plane norm can be calculated using the equation 7 \(\mathrm=6.27 km/s\) is the ambient sound velocity of Al. The \(2\theta\) profile can be used to calculate the interplanar distance according to Bragg’s law 6. In situ XRD is capable of capturing the Debye–Scherrer diffraction cones of the sample at different pressures and projecting these diffraction cones into \(2\theta -\phi\) space, where the Bragg angle \(\theta\) is the angle between the X-ray beam and the family of lattice planes and \(\phi\) is the azimuthal angle around the incident x-ray direction. The development of gas gun 1, pulsed-power 2, and laser drivers 3, combined with in situ x-ray diffraction (XRD) 4, 5, unveiled the structure and phase information of numerous materials under dynamic, high-pressure, shock, and quasi-isentropic compression with strain rates ranging from 10 4 to 10 8 s −1. The advancement in experimental techniques has drastically improved our understanding of solid-phase stability and solid–solid phase transformation under high pressure.
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