scholarly journals Predicting size effects in nickel-base single crystal superalloys with the Discrete-Continuous Model

2010 ◽  
pp. 65-76
Author(s):  
Aurélien Vattré ◽  
Benoit Devincre ◽  
Arjen Roos ◽  
Frédéric Feyel
Keyword(s):  
Mechanical Properties ◽  
Flow Stress ◽  
Finite Elements ◽  
Single Crystal ◽  
Size Effects ◽  
Continuous Model ◽  
Dislocation Dynamics ◽  
Formation And Evolution ◽  
Nickel Base

The Discrete-Continuous Model, a coupling between dislocation dynamics and finite elements simulations, is used for modelling size effects in the mechanical properties of single-crystal superalloys. Both formation and evolution of the dislocation microstructures are analysed, and the crucial role of the storage of signed dislocations at the interfaces is discussed. The onset of plasticity is found to scale as the inverse of the channel width, and polarised dislocation networks at the interfaces significantly increase the flow stress with respect to a bulk crystal.

Predicting size effects in nickel-base single crystal superalloys with the Discrete-Continuous Model

2010 ◽  
Vol 19 (1-3) ◽  
pp. 65-76 ◽  
Author(s):  
Aurélien Vattré ◽  
Benoit Devincre ◽  
Arjen Roos ◽  
Frédéric Feyel
Keyword(s):  
Single Crystal ◽  
Size Effects ◽  
Continuous Model ◽  
Nickel Base

Role of the y/y' Interface on the Mechanical Properties of Single Crystals Nickel Base Superalloys

1998 ◽  
Vol 59-60 ◽  
pp. 185-200 ◽  
Author(s):  
Armand Coujou ◽  
Mustafa Benyoucef ◽  
M. Legros ◽  
Nicole Clément
Keyword(s):  
Mechanical Properties ◽  
Single Crystals ◽  
Nickel Base Superalloys ◽  
Nickel Base

Onset of the Portevin-Le Chatelier Effect: Role of Synchronization of Dislocations

2014 ◽  
Vol 783-786 ◽  
pp. 198-203 ◽  
Author(s):  
Tatiana Lebedkina ◽  
Nikolay P. Kobelev ◽  
Mikhail Lebyodkin
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Collective Motion ◽  
Rate Sensitivity ◽  
Plastic Instability ◽  
Strain Rate Range ◽  
Dislocation Dynamics ◽  
Transient Kinetics ◽  
Kinetic Measurements

The problem of the onset of the Portevin-Le Chatelier (PLC) effect is revised by combining a study of the kinetics of the flow stress evolution upon abrupt changes in the applied strain rate and acoustic emission (AE) accompanying plastic deformation of an AlMg alloy. The kinetic measurements allow evaluating the strain-rate sensitivity of the flow stress and the time characteristics of transient processes as functions of plastic strain. Using known criteria of plastic instability, domains of instability are constructed in the (strain, strain rate) plane. A particular accent is put on the strain-rate range corresponding to the so-called “inverse” behavior. The comparison of such maps with experimental data on the critical strain testifies to the insufficiency of these criteria for explaining the onset of the PLC effect. Moreover, the slow transient kinetics contradicts observations of the fast development of stress drops. The AE measurements bear witness that the stress serrations are associated with bursts in duration of acoustic events generated by the collective motion of dislocations. The possible role of synchronization of dislocation dynamics on the onset of plastic instability is discussed.

Quasicontinuum Simulation of Uniaxial Tension of Single Crystal Copper Nanowire

2011 ◽  
Vol 694 ◽  
pp. 200-204
Author(s):  
Xing Lei Hu ◽  
Ying Chun Liang ◽  
Jia Xuan Chen ◽  
Hong Min Pen
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Molecular Dynamics ◽  
Finite Element ◽  
Single Crystal ◽  
Size Effects ◽  
Tension Test ◽  
Quasicontinuum Method ◽  
Single Crystal Copper ◽  
Copper Nanowire

Quasicontinuum simulations of tension test of single crystal copper nanowire are performed to analyze deformation mechanism of tension process and size effects of mechanical properties. New tension models of nanowire are constructed by using quasicontinuum method, which has combined molecular dynamics and finite element method. Tension processes of three different length nanowires without notches and those with notches are simulated. Yield strength and elastic modulus are calculated according to the obtained load-displacement curves. Finally, the results show that the mechanical properties of copper nanowire have obvious size effect and the notches have obvious influence on the mechanical properties.

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