Quantitative Stress Analysis of Recrystallized OFHC Cu Subject to Deformation In Situ

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Joel V. Bernier ◽  
Matthew P. Miller ◽  
Jun-Sang Park ◽  
Ulrich Lienert
Keyword(s):  
Distribution Function ◽  
Applied Load ◽  
Tensile Deformation ◽  
Elastic Strain Energy ◽  
Weighted Average ◽  
Polycrystalline Materials ◽  
Bound Constraints ◽  
Tensor Fields ◽  
Stress States

Quantitative strain analysis (QSA) provides a means for assessing the orientation-dependent micromechanical stress states in bulk polycrystalline materials. When combined with quantitative texture analysis, it facilitates tracking the evolution of micromechanical states associated with selected texture components for specimens deformed in situ. To demonstrate this ability, a sheet specimen of rolled and recrystallized oxygen-free high conductivity Cu was subject to tensile deformation at APS 1-ID-C. Strain pole figures (SPFs) were measured at a series of applied loads, both below and above the onset of macroscopic yielding. From these data, a lattice strain distribution function (LSDF) was calculated for each applied load. Due to the tensorial nature of the LSDF, the full orientation-dependent stress tensor fields can be calculated unambiguously from the single-crystal elastic moduli. The orientation distribution function (ODF) is used to calculate volume-weighted average stress states over tubular volumes centered on the ⟨100⟩∥[100], ⟨311⟩∥[100], and ⟨111⟩∥[100] fibers—accounting for ≈50% of the total volume—are shown as functions of the applied load along [100]. Corresponding weighted standard deviations are calculated as well. Different multiaxial stress states are observed to develop in the crystal subpopulations despite the uniaxial nature of the applied stress. The evolution of the orientation-dependent elastic strain energy density is also examined. The effects of applying stress bound constraints on the SPF inversion are discussed, as are extensions of QSA to examine defect nucleation and propagation.

scholarly journals Alignment of sample position and rotation during in situ synchrotron X-ray micro-diffraction experiments using a Laue cross-correlation approach

2019 ◽  
Vol 52 (5) ◽  
pp. 1119-1127 ◽  
Author(s):  
Chenglu Zhang ◽  
Yubin Zhang ◽  
Guilin Wu ◽  
Wenjun Liu ◽  
Ruqing Xu ◽  
...  
Keyword(s):  
Tensile Deformation ◽  
Three Dimensional ◽  
Surface Region ◽  
Image Correlation ◽  
Polycrystalline Materials ◽  
X Ray ◽  
Sample Rotation ◽  
Average Grain Size ◽  
Sample Position

Laue micro-diffraction has proven to be able to reveal material properties at the sub-grain scale for many polycrystalline materials and is now routinely available at several synchrotron facilities, providing an approach for nondestructive three-dimensional probing of the microstructures and mechanical states of materials. However, for in situ experiments, maintaining the positioning of the sample throughout the experiment, to achieve a good alignment of the characterized volumes, is a challenging issue. The aim of the present work is to address this problem by developing an approach based on digital image correlation of focused-beam Laue diffraction patterns. The method uses small changes in the diffraction signal as a focused X-ray beam is scanned over a surface region to allow corrections to be made for both sample lateral movement and rotation. The method is demonstrated using a tensile deformation experiment on an Al sample with 2.5 µm average grain size. The results demonstrate an accuracy of 0.5 µm for sample position registration and a precision in sample rotation of ∼0.01°. The proposed method is fast to implement and does not require the use of additional surface markers.

Intragranular three-dimensional stress tensor fields in plastically deformed polycrystals

Science ◽  
2019 ◽  
Vol 366 (6472) ◽  
pp. 1492-1496 ◽  
Author(s):  
Yujiro Hayashi ◽  
Daigo Setoyama ◽  
Yoshiharu Hirose ◽  
Tomoyuki Yoshida ◽  
Hidehiko Kimura
Keyword(s):  
Stress Tensor ◽  
Multiscale Modeling ◽  
Uniform Elongation ◽  
Three Dimensional ◽  
High Energy ◽  
Stress Fields ◽  
Polycrystalline Materials ◽  
Tensor Fields ◽  
Deformation And Failure ◽  
Stress States

The failure of polycrystalline materials used in infrastructure and transportation can be catastrophic. Multiscale modeling, which requires multiscale measurements of internal stress fields, is the key to predicting the deformation and failure of alloys. We determined the three-dimensional intragranular stress tensor fields in plastically deformed bulk steel using a high-energy x-ray microbeam. We observed intragranular local stresses that deviated greatly from the grain-averaged stresses and exceeded the macroscopic tensile strength. Even under deformation smaller than the uniform elongation, the intragranular stress fields were in highly triaxial stress states, which cannot be determined from the grain-averaged stresses. The ability to determine intragranular stress tensor fields can facilitate the understanding and prediction of the deformation and failure of materials through multiscale modeling.

scholarly journals An Improved Algorithm for Measuring Nitrate Concentrations in Seawater Based on Deep-Ultraviolet Spectrophotometry: A Case Study of the Aoshan Bay Seawater and Western Pacific Seawater

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 965
Author(s):  
Xingyue Zhu ◽  
Kaixiong Yu ◽  
Xiaofan Zhu ◽  
Juan Su ◽  
Chi Wu
Keyword(s):  
Weighted Average ◽  
Measuring Method ◽  
Western Pacific ◽  
Nitrate Concentrations ◽  
Deep Ultraviolet ◽  
Ultraviolet Spectrometer ◽  
Seawater Samples ◽  
Reflection Probe

Nowadays, it is still a challenge for commercial nitrate sensors to meet the requirement of high accuracy in a complex water. Based on deep-ultraviolet spectral analysis and a regression algorithm, a different measuring method for obtaining the concentration of nitrate in seawater is proposed in this paper. The system consists of a deuterium lamp, an optical fiber splitter module, a reflection probe, temperature and salinity sensors, and a deep-ultraviolet spectrometer. The regression model based on weighted average kernel partial least squares (WA-KPLS) algorithm together with corrections for temperature and salinity (TSC) is established. After that, the seawater samples from Western Pacific and Aoshan Bay in Qingdao, China with the addition of various nitrate concentrations are studied to verify the reliability and accuracy of the method. The results show that the TSC-WA-KPLS algorithm shows the best results when compared against the multiple linear regression (MLR) and ISUS (in situ ultraviolet spectrophotometer) algorithms in the temperatures range of 4–25 °C, with RMSEP of 0.67 µmol/L for Aoshan Bay seawater and 1.08 µmol/L for Western Pacific seawater. The method proposed in this paper is suitable for measuring the nitrate concentration in seawater with higher accuracy, which could find application in the development of in-situ and real-time nitrate sensors.

scholarly journals Study on Microstructure and In Situ Tensile Deformation Behavior of Fe-25Mn-xAl-8Ni-C Alloy Prepared by Vacuum Arc Melting

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 814
Author(s):  
Yaping Bai ◽  
Meng Li ◽  
Chao Cheng ◽  
Jianping Li ◽  
Yongchun Guo ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Deformation Behavior ◽  
Tensile Deformation ◽  
Austenite Phase ◽  
Vacuum Arc ◽  
Al Content ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Tensile Deformation Behavior

In this study, Fe-25Mn-xAl-8Ni-C alloys (x = 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%) were prepared by a vacuum arc melting method, and the microstructure of this series of alloys and the in situ tensile deformation behavior were studied. The results showed that Fe-25Mn-xAl-8Ni-C alloys mainly contained austenite phase with a small amount of NiAl compound. With the content of Al increasing, the amount of austenite decreased while the amount of NiAl compound increased. When the Al content increased to 12 wt.%, the interface between austenite and NiAl compound and austenitic internal started to precipitate k-carbide phase. In situ tensile results also showed that as the content of Al increased, the alloy elongation decreased gradually, and the tensile strength first increased and then decreased. When the Al content was up to 11 wt.%, the elongation and tensile strength were 2.6% and 702.5 MPa, respectively; the results of in situ tensile dynamic observations show that during the process of stretching, austenite deformed first, and crack initiation mainly occurred at the interface between austenite and NiAl compound, and propagated along the interface, resulting in fracture of the alloy.

In situ pair distribution function analysis of crystallizing Fe-silicate melts

2021 ◽  
Vol 56 (9) ◽  
pp. 5637-5657
Author(s):  
Emily T. Nienhuis ◽  
Manzila Tuheen ◽  
Jincheng Du ◽  
John S. McCloy
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Function Analysis ◽  
Silicate Melts

In-situ EBSD study of the degradation behavior in a type 316 Austenitic Stainless Steel during plastic deformation

2021 ◽  
pp. 030932472098493
Author(s):  
Xiao Wang ◽  
Yuetao Zhang ◽  
Huaying Li ◽  
Ming-yu Huang
Keyword(s):  
Plastic Deformation ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Tensile Deformation ◽  
Target Surface ◽  
Local Orientation ◽  
Deformation Degree ◽  
Band Contrast

Type 316 steels have been heavily utilized as the structural material in many construction equipment and infrastructures. This paper reports the characterization of degradation in 316 austenitic stainless steel during the plastic deformation. The in-situ EBSD results revealed that, with the increase of plastic strain, the band contrast (BC) value progressively decreased in both grain and grain boundaries, and the target surface becomes uneven after the plastic tensile, which indicates that the increase of surface roughness. Meanwhile, the KAM and ρGND values are low in the origin specimen but increased significantly after the in-situ tensile. The results indicated that the KAM and ρGND are closely related to the deformation degree of the materials, which can be used as the indicator for assessing the degradation of 316 steel. Besides, the re-orientation of grain occurred after the tensile deformation, which can be recognized from the lattice orientation and local orientation maps.

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