Transformation Toughening Of Ceramics

Transformation Toughening Of Ceramics
Author: David J. Green
Publisher: CRC Press
Total Pages: 240
Release: 2018-02-06
Genre: Technology & Engineering
ISBN: 1351085859

The aim of this book is to provide a coherent and up-to-date discussion of the scientific work concerning the transformation toughening of ceramics. We hope the book is useful to scientists, engineers and students who are new to these materials. It is intended both as a source of learning and information to those who are new to these materials. It is intended both as a source of learning behaviour and microstructural relationships in transformation-toughened ceramics. While it has been our aim to present a book that is current as possible at the time of publication, the subject is still expanding in many areas; so our hope is that the reader will also gain an insight into the direction of future advances.

Transformation Toughening of Composite Ceramics

Transformation Toughening of Composite Ceramics
Author:
Publisher:
Total Pages: 129
Release: 1990
Genre:
ISBN:

Research is underway into the application of martensitic transformations in ceramics to toughen a variety of ceramic-ceramic composites, i.e., to reduce their brittleness. The toughening agents of interest and their volume changes are dicalcium silicate (Ca2SiO4, 12%), nickel sulfide (NiS, 4%), lanthanide sesquioxides (Ln2O3, 8%) and lutentium borate (LuBO3, 8%). Ceramic processing routes have been developed to fabricate different types of toughened composites, viz., either by using a dispersed second phase microstructure or as a fine grained, single phase material. Specifically, Ca2SiO4 has been dispersed in CaZrO3 and the mechanical properties measured by bend tests. The critical importance of matrix toughness and grain size, as well as role of intergranular microcracking has been established. Dense pellets of fine grained, pure beta- Ca2SiO4 have been sintered and their transformability by grinding established. Their microstructures were examined by TEM and preliminary micromechanical studies made on it, and on Gd2O3, by indentation and SEM techniques. NiS inclusions in glass were examined by TEM and EDS and a sol gel processing route to precipitate NiS in glass has been identified. Composites of Dy2O3 in SiC and powders of LuBO3 in B2O3 have been fabricated.

Tailoring Multiphase and Composite Ceramics

Tailoring Multiphase and Composite Ceramics
Author: Richard E. Tressler
Publisher: Springer Science & Business Media
Total Pages: 783
Release: 2012-12-06
Genre: Technology & Engineering
ISBN: 1461322332

The proceedings of the Twenty-First University Conference on Ceramic Science held at The Pennsylvania State University, University Park, PA on July 17, 18 and 19, 1985 are compiled in this volume "Tailoring Multiphase and Composite Ceramics". This Conference emphasized the' discussion and analysis of the properties of multiphase ceramic materials in which the microstructure is deliberately tailored for specific applications or properties. Inter nationally recognized authorities presented keynote and invited lectures on topics dealing with processing and fabrication of multiphase and com posite electroceramics, fiber reinforced composites and high temperature multiphase ceramics. Results of recent research were presented in oral and poster sessions by leading researchers from several countries. This collection of papers represents the state of the art in our understand ing of the processing-structure-property interrelationships for these materials which possess unique and useful electrical, magnetic, optical, mechanical and thermal properties as a result of their multiphase nature. We are grateful for the financial support of the National Science Foundation, the Office of Naval Research, the Air Force Office of Scien tific Research, and the Defense Advanced Research Projects Agency for this conference. We gratefully acknowledge Prof. Robert Davis' leader ship role in steering and expanding this university conference series on ceramic science. We thank Ron Avillion and Linda Rose for their expert assistance in planning and coordinating the meeting. Thanks are due to Ms. Marian Reed, Ms. Judy Bell and Ms.

Transformation Toughening Of Ceramics

Transformation Toughening Of Ceramics
Author: David J. Green
Publisher: CRC Press
Total Pages: 292
Release: 2018-02-06
Genre: Technology & Engineering
ISBN: 1351094300

The aim of this book is to provide a coherent and up-to-date discussion of the scientific work concerning the transformation toughening of ceramics. We hope the book is useful to scientists, engineers and students who are new to these materials. It is intended both as a source of learning and information to those who are new to these materials. It is intended both as a source of learning behaviour and microstructural relationships in transformation-toughened ceramics. While it has been our aim to present a book that is current as possible at the time of publication, the subject is still expanding in many areas; so our hope is that the reader will also gain an insight into the direction of future advances.

Microstructurally Developed Toughening Mechanisms in Ceramics--Transformation Toughening in the A1 Sub 2 O Sub 3/ZrO Sub 2 Composite System

Microstructurally Developed Toughening Mechanisms in Ceramics--Transformation Toughening in the A1 Sub 2 O Sub 3/ZrO Sub 2 Composite System
Author: F. F. Lange
Publisher:
Total Pages: 30
Release: 1979
Genre:
ISBN:

Three A1203/ZrO2 composites series, containing 0, 2, and 7.5 mole % Y203, respectively, were fabricated. For the A1203/ZrO2(+2M/oY203) series, tetragonal ZrO2 was retained from one end-member to the other. Significant increases in fracture toughness and strength were observed for materials in this system. Strengths decreased with increasing temperature. These results are consistent with previous theoretical predictions. (Author).

Mechanics of Transformation Toughening and Related Topics

Mechanics of Transformation Toughening and Related Topics
Author: J.H. Andreasen
Publisher: Elsevier
Total Pages: 541
Release: 1996-05-01
Genre: Technology & Engineering
ISBN: 0080536042

Since the benefit of stress-induced tetragonal to monoclinic phase transformation of confined tetragonal zirconia particles was first recognized in 1975, the phenomenon has been widely studied and exploited in the development of a new class of materials known as transformation toughened ceramics (TTC). In all materials belonging to this class, the microstructure is so controlled that the tetragonal to monoclinic transformation is induced as a result of a high applied stress field rather than as a result of cooling the material below the martensitic start temperature. The significance of microstructure to the enhancement of thermomechanical properties of TTC is now well understood, as are the mechanisms that contribute beneficially to their fracture toughness. The micromechanics of these mechanisms have been extensively studied and are therefore presented here in a cogent manner. The authors also review dislocation formalism for the modelling of cracks and Eshelby's technique. In compiling this monograph the authors present the most up-to-date and complete review of the field and include several topics which have only recently been fully investigated.

Martensitic Transformation

Martensitic Transformation
Author: Zenji Nishiyama
Publisher: Elsevier
Total Pages: 480
Release: 2012-12-02
Genre: Technology & Engineering
ISBN: 0323148816

Martensitic Transformation examines martensitic transformation based on the known crystallographical data. Topics covered range from the crystallography of martensite to the transformation temperature and rate of martensite formation. The conditions for martensite formation and stabilization of austenite are also discussed, along with the crystallographic theory of martensitic transformations. Comprised of six chapters, this book begins with an introduction to martensite and martensitic transformation, with emphasis on the basic properties of martensite in steels such as carbon steels. The next two chapters deal with the crystallography of martensite and discuss the martensitic transformation behavior of the second-order transition; lattice imperfections in martensite; and close-packed layer structures of martensites produced from ? phase in noble-metal-base alloys. Thermodynamical problems and kinetics are also analysed, together with conditions for the nucleation of martensite and problems concerning stabilization of austenite. The last chapter discusses the theory of the mechanism underlying martensitic transformation. This monograph will be of interest to metallurgists and materials scientists.

Transformation Toughening of Ceramics

Transformation Toughening of Ceramics
Author:
Publisher:
Total Pages: 19
Release: 1995
Genre:
ISBN:

This report summarizes the results from a 3-year research program aimed at developing a basic understanding of the microstructural design, fabrication, and properties of multilayered zirconia-based composites with high toughness and oxidation resistance. Most of the effort focused on multilayered composites of Ce-ZrO2 and Al2O3 which have strongly bonded interfaces. The design of the layered composite microstructure was based on micromechanics analysis: the layers modify the shape and extent of a crack tip transformation zone, leading to toughnesses over 20 MPa.m1/2. Optimum layer thicknesses were determined and related to effects of autocatalytic transformation and crack tip advance mechanisms. Crack resistance curves were measured at various temperatures: the very high toughnesses (> 10 MPa.m1/2) were limited to temperature range of approx. 100 deg C above the Ms temperature for the martensitic transformation. A preliminary study of multilayered composites containing weakly bonded layers (which achieve toughening by debonding) indicated that rare earth phosphates (LaPO4 and CePO4) are potentially suitable layers for Y- and Ce-stabilized zirconia composites. jg.

Designing with Structural Ceramics

Designing with Structural Ceramics
Author: R.W. Davidge
Publisher: Springer Science & Business Media
Total Pages: 352
Release: 2012-12-06
Genre: Technology & Engineering
ISBN: 9401136785

The last 30 years have seen a steady development in the range of ceramic materials with potential for high temperature engineering applications: in the 60s, self-bonded silicon carbide and reaction-bonded silicon nitride; in the 70s, improved aluminas, sintered silicon carbide and silicon nitrides (including sialons); in the 80s, various toughened Zr0 materials, ceramic matrix composites reinforced with silicon 2 carbide continuous fibres or whiskers. Design methodologies were evolved in the 70s, incorporating the principles of fracture mechanics and the statistical variation and time dependence of strength. These have been used successfully to predict the engineering behaviour of ceramics in the lower range of temperature. In spite of the above, and the underlying thermodynamic arguments for operations at higher temperatures, there has been a disappointing uptake of these materials in industry for high temperature usc. Most of the successful applications are for low to moderate temperatures such as seals and bearings, and metal cutting and shaping. The reasons have been very well documented and include: • Poor predictability and reliability at high temperature. • High costs relative to competing materials. • Variable reproducibility of manufacturing processes. • Lack of sufficiently sensitive non-destructive techniques. With this as background, a Europhysics Industrial Workshop sponsored by the European Physical Society (EPS) was organised by the Netherlands Energy Research Foundation (ECN) and the Institute for Advanced Materials of the Joint Research Centre (JRC) of the EC, at Petten, North Holland, in April 1990 to consider the status of thermomechanical applications of engineering ceramics.

Advances in Ceramic Matrix Composites VIII

Advances in Ceramic Matrix Composites VIII
Author: J. P. Singh
Publisher: John Wiley & Sons
Total Pages: 162
Release: 2012-04-11
Genre: Technology & Engineering
ISBN: 1118405927

Ceramic composites are leading candidate materials for high-temperature structural applications. This new book updates readers on the latest in state-of-the-art ceramic composite processing and fabrication methods, process modeling, processing-microstructure-property relationships, mechanical behavior, and characterization. Many of the most important aspects necessary for the understanding and further development of ceramic composites is covered in this volume. It will be of great interest to the technical community involved in advanced ceramic composite processing, characterization, component development, and manufacturing. Proceedings of the symposium held at the 104th Annual Meeting of The American Ceramic Society, April 28-May1, 2002 in Missouri; Ceramic Transactions, Volume 139.