Author: Rachel Louise Morrison
Publisher:
ISBN:
Category : Grain boundaries
Languages : en
Pages : 92
Book Description
This thesis investigates the interaction between gamma' precipitates and grain boundaries in a Ni-Al system during deformation. This interaction is investigated using molecular dynamics, and gamma'/boundary configurations were built to investigate how the orientation, size, and interaction of gamma' change the deformation behavior of the grain boundary. The gamma' aided in nucleating defects (i.e., dislocations) that contributed to the boundary sliding mechanism. By increasing the size of precipitates that bisect the boundary, the boundary becomes stronger, whereas increasing the size of precipitates adjacent to the boundary makes the boundary weaker. Additionally, the interaction of multiple gamma' plays a role in grain boundary sliding behavior. Low concentrations of gamma' produce sliding dominated by atomic shuffling, whereas high concentrations of gamma' produce sliding dominated by dislocation emission. More work is needed to investigate the effects of temperature, initial defects, and different grain boundary configurations on sliding behavior.
Understanding the Interaction Between Grain Boundaries and Precipitates in Ni-Al Using Molecular Dynamics
Author: Rachel Louise Morrison
Publisher:
ISBN:
Category : Grain boundaries
Languages : en
Pages : 92
Book Description
This thesis investigates the interaction between gamma' precipitates and grain boundaries in a Ni-Al system during deformation. This interaction is investigated using molecular dynamics, and gamma'/boundary configurations were built to investigate how the orientation, size, and interaction of gamma' change the deformation behavior of the grain boundary. The gamma' aided in nucleating defects (i.e., dislocations) that contributed to the boundary sliding mechanism. By increasing the size of precipitates that bisect the boundary, the boundary becomes stronger, whereas increasing the size of precipitates adjacent to the boundary makes the boundary weaker. Additionally, the interaction of multiple gamma' plays a role in grain boundary sliding behavior. Low concentrations of gamma' produce sliding dominated by atomic shuffling, whereas high concentrations of gamma' produce sliding dominated by dislocation emission. More work is needed to investigate the effects of temperature, initial defects, and different grain boundary configurations on sliding behavior.
Publisher:
ISBN:
Category : Grain boundaries
Languages : en
Pages : 92
Book Description
This thesis investigates the interaction between gamma' precipitates and grain boundaries in a Ni-Al system during deformation. This interaction is investigated using molecular dynamics, and gamma'/boundary configurations were built to investigate how the orientation, size, and interaction of gamma' change the deformation behavior of the grain boundary. The gamma' aided in nucleating defects (i.e., dislocations) that contributed to the boundary sliding mechanism. By increasing the size of precipitates that bisect the boundary, the boundary becomes stronger, whereas increasing the size of precipitates adjacent to the boundary makes the boundary weaker. Additionally, the interaction of multiple gamma' plays a role in grain boundary sliding behavior. Low concentrations of gamma' produce sliding dominated by atomic shuffling, whereas high concentrations of gamma' produce sliding dominated by dislocation emission. More work is needed to investigate the effects of temperature, initial defects, and different grain boundary configurations on sliding behavior.
Molecular Dynamics Study of Grain Boundary Structure and Properties at High Temperatures
Author: Saryu Jindal Fensin
Publisher:
ISBN: 9781124315690
Category :
Languages : en
Pages :
Book Description
This thesis reports research involving the development and application of atomistic simulation methods to study the effects of high homologous temperatures on the structural, thermodynamic, kinetic and mechanical properties of grain boundaries in metals. In this work we study two different elemental systems, namely Ni and Cu, and consider a variety of grain boundary structures characterized by different misorientation angles, twist/tilt character and zero-temperature energies. A method to calculate the disjoining potential from molecular dynamics is developed and applied to grain boundaries in Ni. The disjoining potential characterizes the variation in grain-boundary free energy as a function of the width of a premelted interfacial layer. The MD method for the calculation of this property is applied to grain boundaries that display continuous premelting transitions, as well as a boundary characterized by a disordered atomic structure displaying a finite interfacial width at the melting temperature. We also develop analysis methods to characterize the change in the atomic structure of an asymmetric tilt grain boundary in elemental Cu as a function of temperature. This boundary is characterized by a potential-energy surface with multiple minima as a function of the relative translation of the grains parallel to the interface plane. The structure of this boundary is found to display both disordering and roughening with increasing temperature. The mobility was calculated at high homologous temperatures using a method based on the analysis of the random walk of the interface in equilibrium MD simulations. Finally, the temperature dependent response of this grain boundary to shear was investigated. The dynamical behavior of the boundary in response to an applied shear strain was observed to undergo qualitative changes as the temperature was increased above 700 K.A decrease in shear resistance of the grain boundaries as a function of temperature was characterized by a decrease in the critical shear stress, an upper bound for which was estimated to be roughly a factor of five lower at the melting temperature than at zero temperature.
Publisher:
ISBN: 9781124315690
Category :
Languages : en
Pages :
Book Description
This thesis reports research involving the development and application of atomistic simulation methods to study the effects of high homologous temperatures on the structural, thermodynamic, kinetic and mechanical properties of grain boundaries in metals. In this work we study two different elemental systems, namely Ni and Cu, and consider a variety of grain boundary structures characterized by different misorientation angles, twist/tilt character and zero-temperature energies. A method to calculate the disjoining potential from molecular dynamics is developed and applied to grain boundaries in Ni. The disjoining potential characterizes the variation in grain-boundary free energy as a function of the width of a premelted interfacial layer. The MD method for the calculation of this property is applied to grain boundaries that display continuous premelting transitions, as well as a boundary characterized by a disordered atomic structure displaying a finite interfacial width at the melting temperature. We also develop analysis methods to characterize the change in the atomic structure of an asymmetric tilt grain boundary in elemental Cu as a function of temperature. This boundary is characterized by a potential-energy surface with multiple minima as a function of the relative translation of the grains parallel to the interface plane. The structure of this boundary is found to display both disordering and roughening with increasing temperature. The mobility was calculated at high homologous temperatures using a method based on the analysis of the random walk of the interface in equilibrium MD simulations. Finally, the temperature dependent response of this grain boundary to shear was investigated. The dynamical behavior of the boundary in response to an applied shear strain was observed to undergo qualitative changes as the temperature was increased above 700 K.A decrease in shear resistance of the grain boundaries as a function of temperature was characterized by a decrease in the critical shear stress, an upper bound for which was estimated to be roughly a factor of five lower at the melting temperature than at zero temperature.
Interactions Between Grain Boundary Faceting, Migration, and Grain Rotation
Author: Yue Huang
Publisher:
ISBN:
Category : Crystals
Languages : en
Pages : 145
Book Description
Publisher:
ISBN:
Category : Crystals
Languages : en
Pages : 145
Book Description
Grain Boundary Segregation in Metals
Author: Pavel Lejcek
Publisher: Springer Science & Business Media
ISBN: 3642125050
Category : Technology & Engineering
Languages : en
Pages : 249
Book Description
Grain boundaries are important structural components of polycrystalline materials used in the vast majority of technical applications. Because grain boundaries form a continuous network throughout such materials, their properties may limit their practical use. One of the serious phenomena which evoke these limitations is the grain boundary segregation of impurities. It results in the loss of grain boundary cohesion and consequently, in brittle fracture of the materials. The current book deals with fundamentals of grain boundary segregation in metallic materials and its relationship to the grain boundary structure, classification and other materials properties.
Publisher: Springer Science & Business Media
ISBN: 3642125050
Category : Technology & Engineering
Languages : en
Pages : 249
Book Description
Grain boundaries are important structural components of polycrystalline materials used in the vast majority of technical applications. Because grain boundaries form a continuous network throughout such materials, their properties may limit their practical use. One of the serious phenomena which evoke these limitations is the grain boundary segregation of impurities. It results in the loss of grain boundary cohesion and consequently, in brittle fracture of the materials. The current book deals with fundamentals of grain boundary segregation in metallic materials and its relationship to the grain boundary structure, classification and other materials properties.
Handbook of Mechanics of Materials
Author: Siegfried Schmauder
Publisher: Springer
ISBN: 9789811068836
Category : Science
Languages : en
Pages : 0
Book Description
This book provides a comprehensive reference for the studies of mechanical properties of materials over multiple length and time scales. The topics include nanomechanics, micromechanics, continuum mechanics, mechanical property measurements, and materials design. The handbook employs a consistent and systematic approach offering readers a user friendly reference ideal for frequent consultation. It is appropriate for an audience at of graduate students, faculties, researchers, and professionals in the fields of Materials Science, Mechanical Engineering, Civil Engineering, Engineering Mechanics, and Aerospace Engineering.
Publisher: Springer
ISBN: 9789811068836
Category : Science
Languages : en
Pages : 0
Book Description
This book provides a comprehensive reference for the studies of mechanical properties of materials over multiple length and time scales. The topics include nanomechanics, micromechanics, continuum mechanics, mechanical property measurements, and materials design. The handbook employs a consistent and systematic approach offering readers a user friendly reference ideal for frequent consultation. It is appropriate for an audience at of graduate students, faculties, researchers, and professionals in the fields of Materials Science, Mechanical Engineering, Civil Engineering, Engineering Mechanics, and Aerospace Engineering.
Grain Boundary Mechanics
Author: Myrjam Winning
Publisher: Cuvillier Verlag
ISBN: 3736921861
Category : Technology & Engineering
Languages : en
Pages : 386
Book Description
Publisher: Cuvillier Verlag
ISBN: 3736921861
Category : Technology & Engineering
Languages : en
Pages : 386
Book Description
Molecular Dynamics Study of Ionic Grain Boundaries
Author: Long-Qing Chen
Publisher:
ISBN:
Category :
Languages : en
Pages : 488
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 488
Book Description
Phase field method and integrated computing materials engineering
Author: Yu-Hong Zhao
Publisher: Frontiers Media SA
ISBN: 2832517374
Category : Technology & Engineering
Languages : en
Pages : 126
Book Description
Publisher: Frontiers Media SA
ISBN: 2832517374
Category : Technology & Engineering
Languages : en
Pages : 126
Book Description
Interactions Between Grain Boundaries and Precipitates in Nimonic PE16 During Grain Growth
Author: V. Randle
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 994
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 994
Book Description