Synchrotron X-ray study of bulk lattice strains in externally loaded Cu-Mo composites

Measuring Stress Distributions in Ti-6Al-4V Using Synchrotron X-Ray Diffraction

“…[15] The shorthand notation, c || s is often used to represent Eq. [2] in the literature. The normal (lattice) strain along c associated with the measured s may then be defined as c ðsÞ…”

“…For this reason, all sources of spatial distortions in the diffraction instrument must be quantified a priori, using a strain-free standard, and subsequently deconvolved from the data. While simplified methods, such as approximating each ring as an ellipse, have been employed to fit strained powder patterns with satisfactory results, [1,2] a more sophisticated, self-consistent method is necessary for generating SPFs for LSDF analysis. [3,8] Our approach is to first correct the raw detector data, using the fiducial CeO 2 pattern, and then fit the g-dependent 2h spectra from the diffraction pattern to the analytic profile functions.…”

“…The combination of rapid collection times and the ability to observe many scattering vectors simultaneously facilitates the performance of thermomechanical processing and performance-like experiments in situ. Experimental techniques have been developed toward this end, to observe both ''bulk'' populations [1][2][3] and individual embedded grains. [4][5][6][7] The data from such experiments can provide an unparalleled level of detail regarding the evolution of micromechanical states during deformation processes.…”

Quantifying Three-Dimensional Residual Stress Distributions Using Spatially-Resolved Diffraction Measurements and Finite Element Based Data Reduction

“…Quantifying the residual stress field within a component using lab source x-rays relies on removing layers of materials from the surface and investigating the newly exposed layers [39], [32], which introduces a significant uncertainty to the stress solution. Penetration through moderate thicknesses (mm-cm) of metallic samples combined with the advantages of high speed area detectors and short collection times have enabled a new generation of high energy synchrotron x-ray diffraction experiments [34], [48], [30], [49], [13], [33], [23], [5]. This large number of lattice strain measurements can be assembled into lattice strain pole figures [15], [46], [36], [33], which can be "inverted" to calculate the orientation-dependent strain and stress tensors within the polycrystalline diffraction volume [3], [47], [6].…”

Elasto-plastic load transfer in bulk metallic glass composites containing ductile particles

“…[6,7,8] The recent availability of high-energy, high-intensity X-rays at third generation synchrotron X-ray facilities has allowed for similar bulk strain measurements in the phases of MMCs. [9,10,11] Advantages of this new technique as compared to neutron diffraction are that small samples can be studied using much shorter data collection times; the associated disadvantage is that the grain size of the phases to be measured must be quite small, typically less than 50 mm. [12] The purpose of the present work is to measure by synchrotron X-ray diffraction the average strains in the metallic reinforcement of BMG composites subjected to uniaxial tensile loads both below and above the limit where plastic deformation of the reinforcement occurs.…”