scholarly journals Coexistence of Two Cubic-Lattice Co Matrices at High Temperatures in Co-Re-Cr-Ni Alloy Studied by Neutron Diffraction

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Přemysl Beran ◽  
Debashis Mukherji ◽  
Pavel Strunz ◽  
Ralph Gilles ◽  
Markus Hölzel ◽  
...  
Keyword(s):  
High Temperature ◽  
Neutron Diffraction ◽  
Diffusion Processes ◽  
Phase Evolution ◽  
Ni Alloy ◽  
The Matrix ◽  
The Face ◽  
Fcc Phase ◽  
In Situ Neutron Diffraction

In situ neutron diffraction measurements were performed during heating to high temperature and cooling for a Co-17Re-23Cr-25Ni alloy. The allotropic transformation of the Co matrix and the evolution of the low-temperature hexagonal and high-temperature cubic Co phases were studied. A surprising observation was the splitting of the face-centred cubic (fcc) Co phase peaks at high temperature during heating as well as cooling. The phase evolution was monitored, and an appearance of the secondary fcc phase could be linked to the formation of σ phase (Cr2Re3 type) associated with a compositional change in the matrix due to diffusion processes at high temperature.

Optimising Sintering in Metal Injection Moulding Using In Situ Neutron Diffraction

2012 ◽  
Vol 706-709 ◽  
pp. 1737-1742 ◽  
Author(s):  
D.J. Goossens ◽  
R.E. Whitfield ◽  
A.J. Studer
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Neutron Diffraction ◽  
Injection Moulding ◽  
Phase Evolution ◽  
Rietveld Analysis ◽  
Formation Temperature ◽  
Lower Temperature ◽  
In Situ Neutron Diffraction

The phase evolution during the sintering of metal injection moulded stainless steel, 316Land 17-4PH, has been observed using in situ neutron diffraction and Rietveld analysis. The formationof the ferrite phase in the final product is associated with the production of -ferrite at high temperatures.Coexistence of phases at high temperature is thought to allow the segregation of alloyingelements, stabilising the ferrite to lower temperature. To prevent ferrite in the final products the sinteringmust occur at a lower temperature than that at which -ferrite is formed. An alternative regimeis proposed in which the temperature would be cycled around the formation temperature of -ferrite.

scholarly journals Tracing Phase Transformation and Lattice Evolution in a TRIP Sheet Steel under High-Temperature Annealing by Real-Time In Situ Neutron Diffraction

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 360 ◽  
Author(s):  
Dunji Yu ◽  
Yan Chen ◽  
Lu Huang ◽  
Ke An
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Neutron Diffraction ◽  
Real Time ◽  
Retained Austenite ◽  
Sheet Steel ◽  
Carbon Diffusion ◽  
Structure Evolution ◽  
In Situ Neutron Diffraction

Real-time in situ neutron diffraction was used to characterize the crystal structure evolution in a transformation-induced plasticity (TRIP) sheet steel during annealing up to 1000 °C and then cooling to 60 °C. Based on the results of full-pattern Rietveld refinement, critical temperature regions were determined in which the transformations of retained austenite to ferrite and ferrite to high-temperature austenite during heating and the transformation of austenite to ferrite during cooling occurred, respectively. The phase-specific lattice variation with temperature was further analyzed to comprehensively understand the role of carbon diffusion in accordance with phase transformation, which also shed light on the determination of internal stress in retained austenite. These results prove the technique of real-time in situ neutron diffraction as a powerful tool for heat treatment design of novel metallic materials.

Use of in situ neutron diffraction to monitor high-temperature, solid/H2-gas reactions

2009 ◽  
pp. 2556 ◽  
Author(s):  
Florent Tonus ◽  
Mona Bahout ◽  
Paul F. Henry ◽  
Siân E. Dutton ◽  
Thierry Roisnel ◽  
...  
Keyword(s):  
High Temperature ◽  
Neutron Diffraction ◽  
Gas Reactions ◽  
In Situ Neutron Diffraction

scholarly journals Method Development for High Temperature In-Situ Neutron Diffraction Measurements of Glass Crystallization on Cooling from Melt

MRS Advances ◽  
2019 ◽  
Vol 4 (17-18) ◽  
pp. 1009-1019 ◽  
Author(s):  
John McCloy ◽  
José Marcial ◽  
Brian Riley ◽  
Jörg Neuefeind ◽  
Jarrod Crum ◽  
...  
Keyword(s):  
High Temperature ◽  
Neutron Diffraction ◽  
High Temperatures ◽  
Method Development ◽  
Temperature Measurements ◽  
Waste Form ◽  
Thin Wall ◽  
Platinum Single Crystal ◽  
In Situ Neutron Diffraction

AbstractA glass-ceramic borosilicate waste form is being considered for immobilization of waste streams of alkali, alkaline-earth, lanthanide, and transition metals generated by transuranic extraction for reprocessing used nuclear fuel. Waste forms are created by partial crystallization on cooling, primarily of oxyapatite and powellite phases. In-situ neutron diffraction experiments were performed to obtain detailed information about crystallization upon cooling from 1200°C. The combination of high temperatures and reactivity of borosilicate glass with typical containers used in neutron experiments, such as vanadium and niobium, prevented their use here. Therefore, methods using sealed thick-walled silica ampoules were developed for the in-situ studies. Unexpectedly, high neutron absorption, low crystal fraction, and high silica container background made quantification difficult for these high temperature measurements. As a follow-up, proof-of-concept measurements were performed on different potential high-temperature container materials, emphasizing crystalline materials so that residual glass in the waste form sample could be more easily analyzed. Room temperature measurements were conducted with a pre-crystallized sample in ‘ideal’ containers stable at low temperatures (i.e., vanadium and thin-wall silica capillaries) and compared to the same measurements in containers stable at high temperatures (i.e, platinum, single crystal sapphire, and thick-walled silica ampoules). Results suggested that Pt is probably the best choice if suitably sealed to prevent contamination from the sample after neutron activation.

Sign in / Sign up

Export Citation Format

Share Document