X-ray Diffraction Contrast Tomography for Polycrystalline Grain Mapping
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Solution Overview
Problem
Conventional X-ray absorption tomography systems fail to provide detailed internal structure information of polycrystalline materials, especially those with homogeneous densities or multiple phases, and are unable to accurately map grain structures and orientations, limiting their non-destructive characterization capabilities.
Innovation Solution
An X-ray diffraction contrast tomography system utilizing a laboratory X-ray source and a second detector positioned to capture diffracted X-ray beams at an angle, allowing a fraction of the direct beam to pass through, along with an X-ray magnifier device to enhance image resolution, enabling more precise grain shape reconstruction and orientation determination without relying on intensity distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a synchrotron X-ray source is used for X-ray diffraction contrast tomography, then detailed three-dimensional grain mapping and orientation analysis can be achieved, but the system becomes less accessible and requires large-scale facilities
Solution Approach 1:
The patent replaces expensive, large-scale synchrotron facilities with a compact laboratory X-ray source. This substitution uses readily available, cost-effective equipment to achieve comparable grain mapping capabilities, making the technology accessible to routine material characterization laboratories without requiring access to national synchrotron facilities
Solution Approach 2:
The patent substitutes the complex mechanical and infrastructural system of synchrotron facilities with a simplified laboratory-based X-ray tube system. This replacement maintains the essential X-ray generation function while eliminating the need for large-scale infrastructure, particle accelerators, and associated support systems
2Measurement precision
If the direct X-ray beam is completely blocked to detect diffracted beams, then diffraction contrast can be measured, but the direct beam information for transmission imaging is lost
Solution Approach 1:
The patent divides the detection function into two separate detectors: one dedicated to detecting the direct transmitted beam for absorption contrast imaging, and another dedicated to detecting diffracted beams for orientation analysis. This segmentation allows both types of information to be captured simultaneously without interference or information loss
Solution Approach 2:
The patent adds a second detection dimension by positioning one detector in the direct beam path and another at an angle to detect diffracted beams. This spatial arrangement in different dimensions allows both direct transmission information and diffraction contrast information to be collected concurrently from the same X-ray source
3Productivity
If spatial filtering criteria are used for grain shape reconstruction, then reconstruction can be performed without analyzing grain orientations, but detailed orientation information is not obtained
Solution Approach 1:
The patent performs preliminary detection of both direct beam transmission data and diffracted beam data simultaneously. By collecting all relevant information in advance through dual detectors, the system enables subsequent reconstruction processes to access complete data sets including orientation information, eliminating the need to choose between speed and information completeness
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This setup makes X-ray diffraction contrast tomography more accessible and efficient, allowing for detailed three-dimensional grain mapping and orientation analysis of polycrystalline materials, even with larger samples, by improving spatial resolution and reducing the need for synchrotron facilities, while maintaining non-destructive characterization.
Implementation Method 1
a first X-ray detector located in the direct path with the staging device positioned between the first X-ray detector and the X-ray source, allowing said first X-ray detector to detect a direct X-ray beam being transmitted through the crystalline material sample
Implementation Method 2
a second X-ray detector positioned in the path of the X-ray beam between the staging device and the first X-ray detector for detecting diffracted X-ray beams leaving the crystalline material sample at an angle
Implementation Method 3
Each time a grain fulfils the Bragg diffraction condition a diffraction contrast occurs
Implementation Method 4
an X-ray magnifier device to enhance image resolution, enabling more precise grain shape reconstruction
Data Source
Figure 1~2
AI summary
An X-ray diffraction contrast tomography system (DCT) comprising a laboratory X-ray source (2),a staging device (5) rotating a polycrystalline material sample in the direct path of the X-ray beam, a first X-ray 10 detector (6) detecting the direct X-ray beam being transmitted through the crystalline material sample,a second X-ray detector (7) positioned between the staging device and the first X-ray detector for detecting diffracted X-ray beams, and a processing device (15) for analysing detected values. The crystallographic grain orientation of the individual 1 grain in the polycrystalline sample is determined based on the two- dimensional position of extinction spots and the associated angular position of the sample for a set of extinction spots pertaining to the individual grain.