High-density three-dimensional mapping of internal strain by tracking microstructural features

Abstract

The three-dimensional strain map is useful to elucidate the relationships between microstructures and locally caused deformation and fracture. However, a robust tracking method, which enables error-free tracking in synchrotoron radiation computed tomography (SR-CT) images with more than ten-thousand microstructural features, is not currently available. In this study, a model sample was subjected to a tensile test and scanned by the SR-CT technique in order to develop a new tracking method. The developed tracking methods indicated a high tracking ratio and tracking success ratio of nearly 100% in a wide strain range, which included the assumed strain in a practical experiment. It was confirmed that tracking errors produce an incorrect strain distribution in three-dimensional strain mapping. This study verified the validity of the developed tracking method. The application of this method to high-resolution SR-CT images will make measurement and visualization of the strain distribution possible in three dimensions in bulk materials.

Four-Dimensional Annihilation Behaviors of Micro Pores during Surface Cold Working

“…This technique is excellent in that it allows not only the four-dimensional (i.e., three-dimensional time evolution) observation of the inside of a material but also the highdensity mapping of internal mechanical quantities by tracing the physical displacement of dispersion particles. [11][12][13] 2. Experimental Method…”

Three dimensional experimental and numerical multiscale analysis of a fatigue crack

“…The use of phase contrast available on modern synchrotron sources was shown to increase crack detection to some extent [15,40] but even in that case only a conservative image of the crack can probably be imaged by tomography. DIC has already been used, in a few studies, on tomographic images [24,28,67] but not with the explicit purpose of detecting cracks.…”

In Situ Observation of Void Nucleation and Growth in a Steel using X-ray Tomography

“…The details of the matching algorithm are described in the reference. 24,25) In this study, the threshold values of M p th1 and M p th2 , which are parameters verifying the validity of the object pair matching, set to 0.8 and 0.1, respectively. The weight parameters, α:β:γ = 0.8:0.1:0.1 were also used.…”

“…24,25) First, tomographic volume image was provided into image processing to find the position, the volume and the surface area of the voids. The home-made software written by the Matlab was used for this quantitative image analysis.…”