Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 35
Get Book Here
Book Description
Brittle intergranular fracture occurs when impurity elements segregate to the grain boundaries of a material and lower their cohesive strength. Although many embrittling elements have been identified by experimental studies, the reason why these elements cause embrittlement has remained elusive. This paper presents results of fully quantum mechanical cluster calculations which address this question. It will be shown that strong embrittling elements draw charge from the neighboring metal atoms onto themselves. They thus remove charge from the metal-metal bonds which hold the grain boundary together and weaken them. Cohesive enhancers do not draw charge off the metal atoms and thus do not weaken the metal-metal bond network. In addition, they form rather homopolar bonds with the metal atoms and thus provide an added increment of bonding in the grain boundary.
Author: C. L. Briant
Publisher: Elsevier
ISBN: 148328865X
Category : Technology & Engineering
Languages : en
Pages : 638
Get Book Here
Book Description
Treatise on Materials Science and Technology, Volume 25: Embrittlement of Engineering Alloys is an 11-chapter text that describes some situations that produce premature failure of several engineering alloys, including steels and nickel- and aluminum-base alloys. Chapters 1 to 3 consider situations where improper alloy composition, processing, and/or heat treatment can lead to a degradation of mechanical properties, even in the absence of an aggressive environment or an elevated temperature. Chapters 4 and 5 examine the effect of elevated temperatures on the mechanical properties of both ferrous and nonferrous alloys. Chapters 6 and 7 discuss the effects of corrosive environments on both stressed and unstressed materials. In these environments anodic dissolution is the primary step that leads to failure. Chapters 8 to 10 deal with the effects of aggressive environments that lead to enhanced decohesion or embrittlement of the metal, such as hydrogen, liquid metal, and irradiation-induced embrittlement. Chapter 11 looks into the embrittlement phenomena occurring during welding, one of the most common processing conditions to which a material could be subjected. This book will prove useful to materials scientists and researchers.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1126
Get Book Here
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Author: R. M. Latanision
Publisher:
ISBN:
Category :
Languages : en
Pages : 24
Get Book Here
Book Description
In this discussion the influence of grain boundary segregates and their interaction with the environment will be discussed with particular reference to hydrogen-induced intergranular embrittlement. Many of the elements which are found segregated at grain boundaries (i.e., the metalloid elements) are catalyst poisons for the hydrogen evolution reaction in electrolytes and, hence, stimulate hydrogen absorption. The use of glassy metal alloys (transition metal-metalloid type) as grain boundary analogs in studying hydrogen absorption and permeation is explored. Likewise, permeation experiments which distinguish between lattice, grain boundary and dislocation transport mechanisms will be discussed. (Author).
Author: Pavel Lejcek
Publisher: Springer Science & Business Media
ISBN: 3642125050
Category : Technology & Engineering
Languages : en
Pages : 249
Get Book Here
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.
Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 388
Get Book Here
Book Description
Author: J.S. Faulkner
Publisher: Springer Science & Business Media
ISBN: 9401110921
Category : Science
Languages : en
Pages : 461
Get Book Here
Book Description
The development of new materials is recognized as one of the major elements in the overall technological evolution that must go on in order to sustain and even improve the quality of life for citizens of all nations. There are many components to this development, but one is to achieve a better understanding of the properties of materials using the most sophisticated scientific tools that are available. As condensed matter physicists and materials scientists work toward this goal, they find that it is useful to divide their efforts and focus on specific areas, because certain analytical and theoretical techniques will be more useful for the study of one class of materials than another. One such area is the study of metals and metallic alloys, which are used in the manufacture of products as diverse as automobiles and space stations. Progress in this area has been very rapid in recent years, and the new developments come from many different countries. For these reasons the Advanced Research Workshop Programme in the NATO Scientific Affairs Division has seen fit to sponsor several meetings to bring together the researchers and students working in this field from the NATO countries and elsewhere. There have been a series of NATO-ASI's that have dealt with the results of research on the electronic structure of materials and the properties of metals, alloys, and interfaces. They are: "Electrons in finite and infinite structures" P. Phariseau and L.
Author: Gary Steven Was
Publisher:
ISBN:
Category : Crystallography
Languages : en
Pages : 380
Get Book Here
Book Description
Materials Science Forum Vol. 46.
Author: W. Wurth Kriegel
Publisher: Springer
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 664
Get Book Here
Book Description
Author: Elena Pereloma
Publisher: Elsevier
ISBN: 0857096109
Category : Technology & Engineering
Languages : en
Pages : 657
Get Book Here
Book Description
The processing-microstructure-property relationships in steels continue to present challenges to researchers because of the complexity of phase transformation reactions and the wide spectrum of microstructures and properties achievable. This major two-volume work summarises the current state of research on phase transformations in steels and its implications for the emergence of new steels with enhanced engineering properties.Volume 1 reviews fundamentals and diffusion-controlled phase transformations. After a historical overview, chapters in part one discuss fundamental principles of thermodynamics, diffusion and kinetics as well as phase boundary interfaces. Chapters in part two go on to consider ferrite formation, proeutectoid ferrite and cementite transformations, pearlite formation and massive austenite-ferrite phase transformations. Part three discusses the mechanisms of bainite transformations, including carbide-containing and carbide-free bainite. The final part of the book considers additional driving forces for transformation including nucleation and growth during austenite-to-ferrite phase transformations, dynamic strain-induced ferrite transformations (DIST) as well as the effects of magnetic fields and heating rates.With its distinguished editors and distinguished international team of contributors, the two volumes of Phase transformations in steels is a standard reference for all those researching the properties of steel and developing new steels in such areas as automotive engineering, oil and gas and energy production. - Discusses the fundamental principles of thermodynamics, diffusion and kinetics - Considers various transformations, including ferrite formation, proeutectoid ferrite and cementite transformations - Considers additional driving forces for transformation including nucleation and growth during austenite-to-ferrite phase transformations
