Precipitation in Al-Cu-Li alloys: from the kinetics of T1 phase precipitation to microstructure development in friction stir welds

2012 ◽  
pp. 1145-1154 ◽  
Author(s):  
A. Deschamps ◽  
F. de Geuser ◽  
B. Decreus ◽  
B. Malard
2021 ◽  
pp. 160583
Author(s):  
N.R. Bochvar ◽  
O.V. Rybalchenko ◽  
N. Yu. Tabachkova ◽  
G.V. Rybalchenko ◽  
N.P. Leonova ◽  
...  

2003 ◽  
Vol 807 ◽  
Author(s):  
Therese Källgren ◽  
Rolf Sandström

ABSTRACTTo ensure safe storage of nuclear fuel waste, copper canisters are proposed as corrosion barrier. One alternative for sealing the copper canisters is Friction Stir Welding (FSW). During the joining process friction heat and mechanical deformation appear between the rotating tool and the material being welded. Liquid metal will not form, since this is a solid state welding process. Three distinct microstructural zones are developed namely the nugget, the thermo-mechanically affected zone (TMAZ) and heat-affected zone (HAZ). The nugget is in the centre of the weld, where the pin is located and where severe plastic deformation occurs that leads to recrystallisation. Surrounding the nugget, the TMAZ is only partially recrystallised, due to lower temperature increase and deformation compared to the nugget. The third zone, HAZ, surrounds the TMAZ. The initial nugget can have a classic round aluminium nugget image, when the welding conditions are cold, but the steady state nugget, is wider near the shoulder and shorter in the weld root.


2008 ◽  
Vol 492 (1-2) ◽  
pp. 35-44 ◽  
Author(s):  
S.J. Barnes ◽  
A. Steuwer ◽  
S. Mahawish ◽  
R. Johnson ◽  
P.J. Withers

2019 ◽  
Vol 38 (2019) ◽  
pp. 567-575 ◽  
Author(s):  
Qingfu Tang ◽  
Dong Chen ◽  
Bin Su ◽  
Xiaopeng Zhang ◽  
Hongzhang Deng ◽  
...  

AbstractThe microstructure evolution of U-Nb alloys during solidification and consequent cooling process was simulated using a cellular automaton (CA) model. By using this model, ϒ phase precipitation and monotectoid decomposition were simulated, and dendrite morphology of ϒ phase, Nb microsegregation and kinetics of monotectoid decomposition were obtained. To validate the model, an ingot of U-5.5Nb (wt.%) was produced and temperature measuring experiment was carried out. As-cast microstructure at different position taken from the ingot was investigated by using optical microscope and SEM. The effect of cooling rate on ϒ phase precipitation and monotectoid decomposition of U-Nb alloys was also studied. The simulated results were compared with the experimental results and the capability of the model for quantitatively predicting the microstructure evolution of U-Nb alloys during solidification and consequent cooling process was assessed.


2010 ◽  
Vol 146-147 ◽  
pp. 1094-1101
Author(s):  
Fei Ding ◽  
Xiao Feng Wang

A numerical model is developed to describe the kinetics of the microstructure evolution in an atomized droplet of Mg-9wt%Al alloy. The model is coupled with the heat transfer controlling equations to simulate the solidification process of the atomized droplets. The numerical results show that the microstructure development is a result of the common action of the nucleation and growth of grains. The nucleation events take place at a critical supercooling for a given droplet. As the droplet size decreases, the critical supercooling increases significantly. The volume fractions of the phases formed during the period of the recalescence, the segregated solidification and the eutectic reaction are sensitive to the droplet size. It is demonstrated that the developed model describes the microstructure evolution process well.


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