Thermal Fatigue Of Metals

Using a mold for centrifugal casting as an example, discusses the types of apparatus and tools that are commonly affected by thermal fatigue during industrial processes, and examines the various factors that lead to such failure. Focuses on the performance of particular industrial components under d

Using a mold for centrifugal casting as an example, discusses the types of apparatus and tools that are commonly affected by thermal fatigue during industrial processes, and examines the various factors that lead to such failure. Focuses on the performance of particular industrial components under d

This volume contains the proceedings of the XIX International Colloquium on Mechanical Fatigue of Metals, held at the Faculty of Engineering of the University of Porto, Portugal, 5-7 September 2018. This International Colloquium facilitated and encouraged the exchange of knowledge and experiences among the different communities involved in both basic and applied research in the field of the fatigue of metals, looking at the problem of fatigue exploring analytical and numerical simulative approaches. Fatigue damage represents one of the most important types of damage to which structural materials are subjected in normal industrial services that can finally result in a sudden and unexpected abrupt fracture. Since metal alloys are still today the most used materials in designing the majority of components and structures able to carry the highest service loads, the study of the different aspects of metals fatigue attracts permanent attention of scientists, engineers and designers.

From concept to application, this book describes the method of strain-range partitioning for analyzing time-dependent fatigue. Creep (time-dependent) deformation is first introduced for monotonic and cyclic loading. Multiple chapters then discuss strain-range partitioning in details for multi-axial loading conditions and how different loading permutations can lead to different micro-mechanistic effects. Notably, the total-strain method of strain-range partitioning (SRP) is described, which is a methodology that sees use in several industries. Examples from aerospace illustrate applications, and methods for predicting time-dependent metal fatigue are critiqued.

The International Symposium "Fatigue under Thermal and Mechanical Loading", held at Petten (The Netherlands) on May 22-24, 1995, was jointly organized by the Institute for Advanced Materials of The Joint Research Centre, E. C. , and by the Societe Fran~se de Metallurgie et de Materiaux. The fast heating and cooling cycles experienced by many high temperature components cause thermally induced stresses, which often operate in combination with mechanical loads. The resulting thermal / mechanical fatigue cycle leads to material degradation mechanisms and failure modes typical of service cycles. The growing awareness that the synergism between the combined thermal and mechanical loads can not be reproduced by means of isothermal tests, has resulted in an increasing interest in thermal and thermo-mechanical fatigue testing. This trend has been reinforced by the constant pull by industry for more performant, yet safer high temperature systems, pushing the materials to the limit of their properties. Dedicated ASTM meetings in particular have set the scene for this area of research. The proceedings of the symposium organized by D. A. Spera and D. F. Mowbray in 1975 provided a reference book on thermal fatigue which reflects the knowledge and experimental capabilities of the mid-seventies.

A computer program called TFLIFE which can be used to predict the thermal fatigue life of metals and structural components from conventional metal properties is described. This program is used as a subroutine with a main program supplied by the user. The main program calculates input cycles of temperature and total strain for TFLIFE which then calculates a stress cycle, creep and plastic strain damage, and cyclic life. A unique feature of TFLIFE is that it calculates lives according to several different failure criteria for the same input data. These criteria are surface crack initiation, interior crack initiation, and complete fracture of both unnotched and notched fatigue specimens. Sample output tables are shown, together with results for two typical problems: (a) thermal-mechanical fatigue of bar specimens of the tantalum alloy T-111 and (b) thermal-stress fatigue of wedge specimens of the nickel alloy B-1900. Thermal fatigue lives calculated using TFLIFE have been verified by comparison with a variety of laboratory test data on different types of alloys. The computer program is now ready for more extensive evaluation on structural components as well as additional laboratory specimens.

A quick and easy to use source for qualified thermal properties of metals and alloys. The data tables are arranged by material hierarchy, with summary tables sorted by property value. Values are given for a range of high and low temperatures. Short technical discussions at the beginning of each chapter are designed to refresh the reader's understanding of the properties and units covered in that section