The Micromechanisms of Cleavage Fracture and Their Relationship to Fracture Toughness in a Bainitic Low Allow Steel
Author: H. Kotilainen
Publisher:
Published: 1980
Total Pages:
ISBN-13:
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Author: H. Kotilainen
Publisher:
Published: 1980
Total Pages:
ISBN-13:
DOWNLOAD EBOOKAuthor: Heikki Kotilainen
Publisher:
Published: 1980
Total Pages: 140
ISBN-13:
DOWNLOAD EBOOKAuthor: Heikki Kotilainen
Publisher:
Published: 1980
Total Pages: 133
ISBN-13:
DOWNLOAD EBOOKAuthor: Jianhong Chen
Publisher: Butterworth-Heinemann
Published: 2014-09-15
Total Pages: 488
ISBN-13: 0128010517
DOWNLOAD EBOOKIn this book the authors focus on the description of the physical nature of cleavage fracture to offer scientists, engineers and students a comprehensive physical model which vividly describes the cleavage microcracking processes operating on the local (microscopic) scale ahead of a defect. The descriptions of the critical event and the criteria for cleavage fracture will instruct readers in how to control the cleavage processes and optimize microstructure to improve fracture toughness of metallic materials. - Physical (mechanical) processes of cleavage fracture operating on the local (microscopic) scale, with the focus on the crack nucleation and crack propagation across the particle/grain and grain/grain boundaries - Critical event, i.e., the stage of greatest difficulty in forming the microcrack, which controls the cleavage fracture - Criteria triggering the cleavage microcracking with incorporation of the actions of macroscopic loading environment into the physical model - Effects of microstructure on the cleavage fracture, including the effects of grain size, second phase particles and boundary - Comprehensive description of the brittle fracture emerging in TiAl alloys and TiNi memory alloys
Author:
Publisher:
Published: 1991
Total Pages: 1460
ISBN-13:
DOWNLOAD EBOOKLists 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: A. R. Rosenfield
Publisher:
Published: 1986
Total Pages: 14
ISBN-13:
DOWNLOAD EBOOKA complete understanding of the fracture mechanisms of steel in the ductile/brittle transition region requires analysis not only of crack initiation, but also of crack propagation. This paper reviews micrographic and fractographic experiments that give insight into both phenomena, and suggests a frame-work through which both may be related. Unstable cleavage crack initiation can occur after some blunting of the original fatigue precrack or after some stable crack growth. In either event, instability appears to be triggered by the fracture of a brittle micro-constituent ahead of the precrack. The large scatter in reported KIc values within the transition region reflects the size distribution and relative scarcity of these trigger particles. While a large number of models have attempted to correlate toughness in the ductile/brittle transition regime to events occurring ahead of the crack tip, surprisingly little attention has been paid to events occurring behind the crack front. Fractographic evidence as well as metallographic sectioning of arrested cracks show that the mechanism of rapid crack propagation by cleavage is affected strongly by partial crack-plane deflection which leaves unbroken ligaments in its wake. The tearing of these ligaments by dimple-rupture is the dominant energy-absorbing mechanism. Etch-pit experiments using an Fe-Si alloy show that the crack-tip stress intensity based on plastic zone size is extremely low. Keywords: HSLA(High Strength Low Alloy), Ductile fracture, Shear fracture, Fracture toughness.
Author: Syavash Ensha
Publisher:
Published: 1974
Total Pages: 198
ISBN-13:
DOWNLOAD EBOOKA theoretical model has been used to relate the cleavage fracture toughness of the low-alloy steels to their microstructure. The cleavage fracture toughness of low-alloy steels depends upon three metallurgical parameters: the microscopic cleavage strength, the yield strength, and the effective root radius. Variations in fracture toughness with microstructure can be explained through the effect of the microstructure on these parameters. The major objective of this investigation has been the study of the effect of microstructural variables on these parameters, and hence the effect of microstructure on fracture toughness. The theoretical model for the cleavage fracture toughness of the low-alloy steels can be successfully applied provided the assumptions are not strongly violated. This requires low microscopic cleavage strength/yield strength ratio values and low work-hardening rates. Lower temperatures and higher strain rates both favor these conditions. (Modified author abstract).
Author: G. D. Whitman
Publisher:
Published: 1981
Total Pages: 146
ISBN-13:
DOWNLOAD EBOOKAuthor: David Taylor
Publisher: Elsevier
Published: 2010-07-07
Total Pages: 307
ISBN-13: 0080554725
DOWNLOAD EBOOKCritical distance methods are extremely useful for predicting fracture and fatigue in engineering components. They also represent an important development in the theory of fracture mechanics. Despite being in use for over fifty years in some fields, there has never been a book about these methods – until now. So why now? Because the increasing use of computer-aided stress analysis (by FEA and other techniques) has made these methods extremely easy to use in practical situations. This is turn has prompted researchers to re-examine the underlying theory with renewed interest. The Theory of Critical Distances begins with a general introduction to the phenomena of mechanical failure in materials: a basic understanding of solid mechanics and materials engineering is assumed, though appropriate introductory references are provided where necessary. After a simple explanation of how to use critical distance methods, and a more detailed exposition of the methods including their history and classification, the book continues by showing examples of how critical distance approaches can be applied to predict fracture and fatigue in different classes of materials. Subsequent chapters include some more complex theoretical areas, such as multiaxial loading and contact problems, and a range of practical examples using case studies of real engineering components taken from the author's own consultancy work. The Theory of Critical Distances will be of interest to a range of readers, from academic researchers concerned with the theoretical basis of the subject, to industrial engineers who wish to incorporate the method into modern computer-aided design and analysis. - Comprehensive collection of published data, plus new data from the author's own laboratories - A simple 'how-to-do-it' exposition of the method, plus examples and case studies - Detailed theoretical treatment - Covers all classes of materials: metals, polymers, ceramics and composites - Includes fracture, fatigue, fretting, size effects and multiaxial loading
Author: The Minerals, Metals & Materials Society (TMS)
Publisher: John Wiley & Sons
Published: 2015-04-15
Total Pages: 952
ISBN-13: 1119027985
DOWNLOAD EBOOKThis DVD contains a collection of papers presented at EnergyMaterials 2014, a conference organized jointly by The ChineseSociety for Metals (CSM) and The Minerals, Metals & MaterialsSociety (TMS), and held November 4-6, 2014, in Xi’an, ShaanxiProvince, China. With the rapid growth of the world’s energyproduction and consumption, the important role of energy materialshas achieved worldwide acknowledgement. Material producers andconsumers constantly seek the possibility of increasing strength,improving fabrication and service performance, simplifyingprocesses, and reducing costs. Energy Materials 2014 has provided aforum for academics, researchers, and engineers around the world toexchange state-of-the-art development and information on issuesrelated to energy materials. The papers on the DVD are organized around the followingtopics: Materials for Coal-Based Systems Materials for Gas Turbine Systems Materials for Nuclear Systems Materials for Oil and Gas Materials for Pressure Vessels