Fatigue Failure of Metals

ISBN-13: 9789028600256 / Angielski / Twarda / 1978 / 368 str.

S. Kocanda

Opis

The studies on the phenomena of fatigue in metals, and especially on the formation and growth rate of cracks have been conducted in 1972-1974 with continued intensity. Their results contribute to expanding our knowledge and give us a new insight into the sphere of metal fatigue which is a highly interdiscipline field. This makes the continuous amending and modifying of books on metal fatigue a necessity, unfortunately often related with the not easy task of changing one's opinions and critical analysis of established earlier notions. These aims were my chief concern when preparing the present edition of my book in which I made use of carefully selected new information from 1972-1973 and partly 1974 reports. This new matter has been included in many instances just to signal new facts or findings, since the limited space did not allow me to give them the amount of consideration they deserve. The book has been further supplemented with the results of micrographic studies conducted in co-operation with J. Kozubowski for which lowe him special thanks. I am also indebted to Mr. H. Mughrabi from Stuttgart for allowing me to publish in this book his very interesting micrographs of dislocation structures. Finally I should like to express my sincere thanks to Mr. E. Lepa for his concern in producing a good English translation of my book.

Spis treści

1 Fundamental concepts and fatigue processes.- 1.1 Fatigue stresses.- 1.2 Wöhler fatigue diagrams.- 1.3 The low-cycle range.- 1.3.1 General testing methods. Fundamental formulae.- 1.3.2 The influence of various factors and testing conditions. Hardening and softening hypotheses.- 1.4 The stages in fatigue processes.- References.- 2 Fatigue phenomena.- 2.1 Introductory remarks.- 2.2 Slip bands.- 2.2.1 Slip bands in the region above the fatigue limit.- 2.2.2 Slip bands in the range below the fatigue limit.- 2.3 Extrusions and intrusions.- 2.3.1 Extrusions and intrusions in polycrystalline iron and copper.- 2.3.2 Models and hypotheses of extrusion and intrusion formation.- 2.4 Fatigue cracks.- 2.4.1 Crack sources and propagation.- 2.4.2 Microcracks in polycrystalline iron.- 2.5 Supplementary methods of studying fatigue phenomena.- 2.5.1 Fatigue phenomena and changes in physical properties.- 2.5.2 Ionic bombardment (etching) method.- 2.5.3 The thermal etching method.- 2.5.4 Fatigue phenomena and surface microroughness.- 2.6 A survey of studies on fatigue changes in different metals.- 2.6.1 Face-centered cubic metals and alloys.- 2.6.2 Body-centered cubic metals and alloys.- 2.6.3 Hexagonal close-packed metals.- 2.6.4 Microcracks initiation in electroplated steel samples.- 2.7 Theories of fatigue.- 2.7.1 General remarks and early theories.- 2.7.2 Dislocation theories and crack initiation models.- 2.7.3 Statistical theories.- 2.7.4 Energy theories.- References.- 3 Fatigue dislocation structures.- 3.1 Introduction.- 3.2 The dislocation structure in face-centered cubic metals and alloys.- 3.2.1 Copper and its alloys.- 3.2.2 Aluminium and aluminium alloys.- 3.2.3 Austenitic steels.- 3.2.4 Other metals and alloys.- 3.3 The dislocation structure in body-centered cubic metals and alloys.- 3.3.1 Iron and iron alloys.- 3.3.2 Non-ferrous metals and alloys.- 3.4 The dislocation structure in hexagonal close-packed metals and alloys.- 3.5 An attempt at a synthesis.- References.- 4 Fatigue crack growth.- 4.1 General remarks.- 4.2 Description of crack growth.- 4.3 Fundamental relations for determining the fatigue crack growth rate.- 4.4 The influence of loading conditions on fatigue crack propagation rates. Sundry problems (Examples).- 4.5 Non-propagating fatigue cracks.- References.- 5 Fatigue fractures.- 5.1 Introduction.- 5.2 Classification of fractures and their characteristic features.- 5.2.1 General classification of fractures.- 5.2.2 The fundamental types of fracture.- 5.3 The macrostructure of fatigue fractures.- 5.3.1 Specific features of fracture surfaces.- 5.3.2 The macrostructure of fractures and the loading mode (Examples).- 5.4 The microstructure of fatigue fractures.- 5.4.1 General remarks.- 5.4.2 Fatigue striations.- 5.4.3 Tire tracks.- 5.4.4 Examples of fracture microstructure and their interpretations.- 5.4.5 Concluding remarks.- References.