ON THE MEASUREMENT AND INTERPRETATION OF RESIDUAL STRESS AT THE MICRO-SCALE

2010 ◽  
Vol 24 (01n02) ◽  
pp. 1-9 ◽  
Author(s):  
ALEXANDER M. KORSUNSKY ◽  
EDOARDO BEMPORAD ◽  
MARCO SEBASTIANI ◽  
FELIX HOFMANN ◽  
SARAANSH DAVE

In the present paper we consider two representative methods for residual stress evaluation at the micro-scale: a (semi-)destructive method involving material removal and the measurement of strain relief; and a non-destructive X-ray diffraction technique involving the use of micro-focused synchrotron X-ray beam. A recently developed strain relief approach is described using a Focused Ion Beam (FIB) to create a circular trench of progressively increasing depth around a circular "island". Residual stress is evaluated by the comparison of the strain relief (measured by digital correlation of displacements or strains) with Finite Element simulations. The technique is illustrated for a thin TiN coating layer. The second approach uses focused synchrotron X-ray beams for white beam Laue diffraction. Demonstration experiments described involve in situ loading of commercially pure nickel foil. Procedures for validation and improvement of accuracy are discussed.

2021 ◽  
Vol 28 (2) ◽  
pp. 550-565 ◽  
Author(s):  
David Yang ◽  
Nicholas W. Phillips ◽  
Kay Song ◽  
Ross J. Harder ◽  
Wonsuk Cha ◽  
...  

Focused ion beam (FIB) techniques are commonly used to machine, analyse and image materials at the micro- and nanoscale. However, FIB modifies the integrity of the sample by creating defects that cause lattice distortions. Methods have been developed to reduce FIB-induced strain; however, these protocols need to be evaluated for their effectiveness. Here, non-destructive Bragg coherent X-ray diffraction imaging is used to study the in situ annealing of FIB-milled gold microcrystals. Two non-collinear reflections are simultaneously measured for two different crystals during a single annealing cycle, demonstrating the ability to reliably track the location of multiple Bragg peaks during thermal annealing. The thermal lattice expansion of each crystal is used to calculate the local temperature. This is compared with thermocouple readings, which are shown to be substantially affected by thermal resistance. To evaluate the annealing process, each reflection is analysed by considering facet area evolution, cross-correlation maps of the displacement field and binarized morphology, and average strain plots. The crystal's strain and morphology evolve with increasing temperature, which is likely to be caused by the diffusion of gallium in gold below ∼280°C and the self-diffusion of gold above ∼280°C. The majority of FIB-induced strains are removed by 380–410°C, depending on which reflection is being considered. These observations highlight the importance of measuring multiple reflections to unambiguously interpret material behaviour.


CORROSION ◽  
10.5006/3881 ◽  
2021 ◽  
Author(s):  
Zachary Karmiol ◽  
Dev Chidambaram

This work investigates the oxidation of a nickel based superalloy, namely Alloy X, in water at elevated temperatures: subcritical water at 261°C and 27 MPa, the transition between subcritical and supercritical water at 374°C and 27 MPa, and supercritical water at 380°C and 27 MPa for 100 hours. The morphology of the sample surfaces were studied using scanning electron microscopy coupled with focused ion beam milling, and the surface chemistry was investigated using X-ray diffraction, Raman spectroscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy before and after exposure studies. Surfaces of all samples were identified to comprise of a ferrite spinel containing aluminum.


2016 ◽  
Vol 49 (2) ◽  
pp. 700-704 ◽  
Author(s):  
Paul A. Shade ◽  
David B. Menasche ◽  
Joel V. Bernier ◽  
Peter Kenesei ◽  
Jun-Sang Park ◽  
...  

An evolving suite of X-ray characterization methods are presently available to the materials community, providing a great opportunity to gain new insight into material behavior and provide critical validation data for materials models. Two critical and related issues are sample repositioning during an in situ experiment and registration of multiple data sets after the experiment. To address these issues, a method is described which utilizes a focused ion-beam scanning electron microscope equipped with a micromanipulator to apply gold fiducial markers to samples for X-ray measurements. The method is demonstrated with a synchrotron X-ray experiment involving in situ loading of a titanium alloy tensile specimen.


1988 ◽  
Vol 142 ◽  
Author(s):  
John F. Porter ◽  
Dan O. Morehouse ◽  
Mike Brauss ◽  
Robert R. Hosbons ◽  
John H. Root ◽  
...  

AbstractStudies have been ongoing at Defence Research Establishment Atlantic on the evaluation of non-destructive techniques for residual stress determination in structures. These techniques have included neutron diffraction, x-ray diffraction and blind-hole drilling. In conjunction with these studies, the applicability of these procedures to aid in metallurgical and failure analysis investigations has been explored. The x-ray diffraction technique was applied to investigate the failure mechanism in several bent turbo blower rotor shafts. All examinations had to be non-destructive in nature as the shafts were considered repairable. It was determined that residual stress profiles existed in the distorted shafts which strongly indicated the presence of martensitic microstuctures. These microstructures are considered unacceptable for these shafts due to the potential for cracking or in-service residual stress relaxation which could lead to future shaft distortion.


2020 ◽  
Vol 60 (4) ◽  
pp. 475-480
Author(s):  
V. A. N. Righetti ◽  
T. M. B. Campos ◽  
L. B. Robatto ◽  
R. R. Rego ◽  
G. P. Thim

1994 ◽  
Vol 299 ◽  
Author(s):  
Gary A. Gibson ◽  
Davis A. Lange ◽  
Charles M. Falco

AbstractWe have used Molecular Beam Epitaxy (MBE) to successfully grow films that are predominantly IrSi3 on both Si(111) and Si(100) substrates by codeposition of Si and Ir in a 3:1 ratio. Bragg-Brentano and Seemann-Bohlin x-ray diffraction reveal that polycrystalline IrSi3 films form as low as 450 °C. This is the lowest temperature yet reported for growth of this iridium silicide phase. These x-ray diffraction techniques, along with Transmission Electron Microscope (TEM) diffraction and in situ Low Energy Electron Diffraction (LEED), show that at higher deposition temperatures codeposition can form IrSi3 films on Si(111) that consist predominantly of a single epitaxial growth orientation. Ion beam channeling and x-ray rocking curves show that the epitaxial quality of IrSi3 films deposited on Si(111) is superior to that of IrSi3 films deposited on Si(100). We also present evidence for several new epitaxial IrSi3 growth modes on Si(111) and Si(100).


1988 ◽  
Vol 126 ◽  
Author(s):  
John F. Knudsen ◽  
R. C. Bowman ◽  
P. M. Adams ◽  
R. Newman ◽  
J. P. Hurrell ◽  
...  

ABSTRACTEpitaxial regrowth of deposited amorphous silicon has been previously described utilizing ion implantation amorphization, ion mixing and thermal anneal. This paper evaluates the effects of these process steps on crystalline quality utilizing Rutherford Backscattering (RBS), x-ray diffraction rocking curves and Raman scattering.In situ (during implantation) regrowth results in defective crystallinity. In contrast, when there is no in situ regrowth, the post anneal crystallinity is equivalent by RBS and x-ray evaluation to virgin single crystal wafers. In situ regrowth is most pronounced during the high beam current ion mixing type implants which produce wafer temperatures of about 250°C. The final crystalline quality which results from different sequences of amorphization and ion mixing implants, is strongly dependent upon the amount of in situ regrowth which has occurred. The greater the in situ regrowth the poorer the final crystalline quality.


Sign in / Sign up

Export Citation Format

Share Document