A Mirror Furnace for In Situ Residual Stress Measurements by Neutron Diffraction

2014 ◽  
Vol 777 ◽  
pp. 31-34
Author(s):  
Jian Bo Gao ◽  
Dong Feng Chen ◽  
Jun Hong Li ◽  
Yun Tao Liu
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Stress Measurements ◽  
Powder Diffractometer ◽  
Neutron Powder Diffractometer ◽  
The Stability ◽  
Better Than

A mirror furnace for in situ residual stress measurements by neutron diffraction is designed. Bulk and stick sample can be in situ heated up to 1000 degrees centigrade. The stability of the temperature is better than ±1 degree centigrade. This furnace is designed mainly for residual stress neutron diffraction experiments. And also it can be applied to some other neutron instruments such as neutron texture diffractometer, neutron powder diffractometer and triple axis spectrometer.

In Situ Thin Film Stress Measurements – A Path to Understanding the Structure and Morphology of Electron Beam Evaporated ZnS

2002 ◽  
Vol 749 ◽  
Author(s):  
Vincent Barrioz ◽  
Stuart J. C. Irvine ◽  
D. Paul
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Electron Beam ◽  
Stress Reduction ◽  
Float Glass ◽  
Film Stress ◽  
Intrinsic Stress ◽  
Ex Situ ◽  
Stress Measurements

ABSTRACTZnS is a material of choice in the optical coating industry for its optical properties and broad transparency range. One of the drawbacks of ZnS is that it develops high compressive intrinsic stress resulting in large residual stress in the deposited layer. This paper concentrates on the evolution of residual stress reduction in ZnS single layers, depending upon their deposition rate or the substrate temperature during deposition (i.e. 22 °C and 133 °C). The substrate preparation is addressed for consideration of layer adhesion. Residual stress of up to − 550 MPa has been observed in amorphous/poor polycrystalline ZnS layers, deposited on CMX and Float glass type substrates, by electron beam evaporation at 22 °C, with a surface roughness between 0.4 and 0.8 nm. At 133 °C, the layer had a surface roughness of 1 nm, the residual stress in the layer decreased to − 150 MPa, developing a wurtzite structure with a (002) preferred orientation. In situ stress measurements, using a novel optical approach with a laser-fibre system, were carried out to identify the various sources of stress. A description of this novel in situ stress monitor and its advantages are outlined. The residual stress values were supported by two ex situ stress techniques. The surface morphology analysis of the ZnS layers was carried out using an atomic force microscope (AFM), and showed that stress reduced layers actually gave rougher surfaces.

Residual Stress Measurements in Thick Structural Weldments by Means of Neutron Diffraction*

2000 ◽  
Vol 347-349 ◽  
pp. 658-663 ◽  
Author(s):  
Carsten Ohms ◽  
Anastasius Youtsos ◽  
P. v.d. Idsert ◽  
Th. Timke
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Stress Measurements

Influence of Accelerator Residues on Age Resistance of Vulcanizates

1960 ◽  
Vol 33 (2) ◽  
pp. 490-501
Author(s):  
Z. T. Ossefort
Keyword(s):  
Zinc Oxide ◽  
Natural Rubber ◽  
Network Structure ◽  
Dual Process ◽  
Curing Process ◽  
Active Inhibitor ◽  
The Stability ◽  
Prime Function ◽  
Better Than

Abstract It has been shown that the age resistance of elastomeric vulcanizates is influenced to a very marked degree by residues formed in situ in the vulcanizate during the curing process. By a dual process of removal of these residues and incorporation of selected ingredients subsequent to vulcanization, it has been shown that age resistance (as measured by accelerated oven-aging tests at 212° F) in rubbers cured by sulfur and/or sulfur bearing accelerators, is a prime function of these residues and nearly independent of the stability of the network structure. An extremely active inhibitor is formed in situ during vulcanization of SBR and natural rubber using thiuram accelerators. This inhibitor can be used to “reinhibit” acetone-extracted accelerator-cured rubber. When added to sulfur/accelerator, peroxide, or radiation-cured vulcanizates, it improves their age resistance, but only in the case of the sulfur/accelerator cured rubber is this improvement better than with conventional inhibitors. This leads to the conclusion that the efficiency with which an inhibitor protects a vulcanizate varies widely, and conversely it appears that certain types of network structures are more readily protected or that certain inhibitors can function more efficiently in the protection of certain structures than others. In the case of natural rubber cured with TMTD (zinc oxide present), the bulk of the accelerator residue is ZnDMDC, and this residue has been shown to function as a very efficient antioxidant when incorporated into acetone-extracted, accelerator-cured vulcanizate. It is no more effective than conventional inhibitors, however, when incorporated into an acetone-extracted, sulfur/accelerator-cured vulcanizate. Finally, it has been shown that acetone extraction of the various vulcanizates may lead to improvement or worsening of their age resistance, depending upon the nature of the residues resulting from the curing process.

G030031 Internal Residual Stress Measurements of Aluminum Alloy Castings Using Neutron Diffraction

2011 ◽  
Vol 2011 (0) ◽  
pp. _G030031-1-_G030031-5
Author(s):  
Yumi KUBOTA ◽  
Jun KUBO ◽  
Keitaro ISHIDA ◽  
Akinori OKADA ◽  
Minoru YOSHIDA ◽  
...  
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Neutron Diffraction ◽  
Stress Measurements ◽  
Alloy Castings

Measurement of Residual Stress Shakedown in Pressure/Tensile Armour Wires of Flexible Pipes by Neutron Diffraction

2015 ◽  
Author(s):  
Upul S. Fernando ◽  
Michelle Davidson ◽  
Christopher Simpson ◽  
Thilo Pirling ◽  
Kun Yan ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Metal Layer ◽  
Diffraction Method ◽  
Acceptance Test ◽  
Flexible Pipes ◽  
Before And After ◽  
Unbonded Flexible Pipes ◽  
Hoop Stresses

The manufacture of unbonded flexible pipes (flowlines and risers) involves wrapping steel wires to create pressure and tensile armour layers. The forming of armour wires from vendor supply conditions to a helix shape on the pipe involves significant plastic straining and the wires that are wrapped onto the pipe are not unloaded. Therefore the armour wires in flexible pipes are expected to contain significant residual stress (RS) as a result of the plastic straining and loading during manufacture and placement. This may lead to detrimental effects on the strength, durability and the service integrity of the pipe. It is postulated that the unfavorable RS introduced during pipe manufacture reduces due to stress shakedown during the factory acceptance test (FAT) where the pipe is subjected to a high internal pressure. This paper describes the first attempts to measure RS in the armour wires in unbonded flexible pipes. The key development is the use of a neutron diffraction method which allows the measurement of RS in-situ on the manufactured pipe through the whole wire sections. Pipe samples were prepared exposing the relevant metal layer and the measurements were performed on pipe samples taken before and after performing the pressurized FAT. The effect of the FAT on the shakedown of residual stress in pressure armour wires is discussed. As shown by the measurements, the elastic strains and stresses in the pressure armour wires are much larger in the hoop direction of the pipe (i.e. along the length of the wire) than radial or axial to the pipe. In pre-FAT pipe the hoop stresses are essentially tensile on the extrados and compressive on the intrados. The results have shown that the FAT reduces the hoop strains and stresses to approximately 1/3 of their as manufactured level.

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