ASM Metals HandBook Volume 12 - Fractography
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improvements over the light microscope: it extends the resolution limits so that picture magnification can be increased from 1000 to 2000× (maximum useful magnification for the light microscope) up to 30,000 to 60,000×, and it improves the depth-of-field resolution from 100 to 200 nm for the light microscope to 4 to 5 nm (Ref 109). Application to Fractography. The first paper to discuss the use of scanning electron microscope for the study of fracture surfaces was published in 1959 by Tipper, Dagg, and Wells (Ref 110). Cleavage fractures in \u3b1-iron specimens were shown. Two years later, Laird and Smith used the scanning electron microscope to show that fatigue striations occur at the beginning of fracture in a high stress failure; this was not apparent when using optical fractography (Ref 111). Soon afterward, McGrath et al. used the scanning electron microscope to study fracture surfaces of copper tested in fatigue and 24S-T aluminum alloy (equivalent to present-day 2024) tested in fatigue and impact (Ref 112). The fractographs in this report approached the quality of those published today. However, because of the slow commercial development of the instrument and the popularity of the transmission electron microscope and associated fracture replication techniques, the potential of the scanning electron microscope for fracture studies was not realized until the early 1970s (Ref 2, 113, 114). Today, fractography is one of the most popular applications of the scanning electron microscope. The large depth of focus, the possibility of changing magnification over a wide range, very simple nondestructive specimen preparation with direct inspection, and the three-dimensional appearance of scanning electron microscope fractographs make the instrument a vital and essential tool for fracture research. Additional information on the scanning electron microscope and its application to fractography can be found in the article "Scanning Electron Microscopy" in this Volume. An extensive review of the principles, instrumentation, and applications of the scanning electron microscope is available in Ref 109. Important Literature. Over the past 15 years, hundreds of papers have been published featuring scanning electron microscope fractographs. Of particular note are several Handbooks and Atlases, which illustrate the utility of the instrument for fracture studies. In August of 1974, the American Society for Metals published Volume 9, Fractography and Atlas of Fractographs, of the 8th Edition of Metals Handbook. This was the first extensive collection of scanning electron microscope fractographs ever published. From 15 October 1973 to 15 June 1975, engineers at McDonnell Douglas Astronautics Company prepared the SEM/TEM Fractography Handbook, which was subsequently published in December of 1975 (Ref 115). Unique to this Volume were the numerous comparisons of scanning electron fractographs with transmission electron fractographs obtained from replicas. From 1969 to 1972, funded research performed at IIT Research Institute under the direction of Om Johari resulted in the IITRI Fracture Handbook, published in January of 1979 (Ref 116). Hundreds of fractographs of ferrous materials, aluminum-base alloys, nickel-base alloys, and titanium-base alloys were shown. In 1981, Engel and Klingele published An Atlas of Metal Damage (Ref 117). This Atlas illustrates fracture surfaces as well as surfaces damaged due to wear, chemical attack, melting of metals or glasses, or high-temperature gases. Quantitative Fractography (Ref 118) The availability of the scanning electron microscope opened up new avenues toward the understanding of fracture surfaces in three dimensions and the subsequent interest in quantitative fractography. The goal of quantitative fractography is to express the features and important characteristics of a fracture surface in terms of the true surface areas, lengths, sizes, numbers, shapes, orientations, and locations, as well as distributions of these quantities. With an enhanced capability for quantifying the various features of a fracture, engineers can perform better failure analyses, can better determine the relationship of the fracture mode to the microstructure, and can develop new materials and evaluate their response to mechanical, chemical, and thermal environments. Detailed descriptions of the historical development of quantitative fractography and associated quantification techniques can be found in the articles "Quantitative Fractography" and "Fractal Analysis of Fracture Surfaces" in this Volume. Supplementary information can be found in the article "Scanning Electron Microscopy." References cited in this section 2. J.L. McCall, "Failure Analysis by Scanning Electron Microscopy," MCIC Report, Metals and Ceramics Information Center, Dec 1972 4. J.L. McCall, Electron Fractography--Tools and Techniques, in Electron Fractography, STP 436, American Society for Testing and Materials, 1968, p 3-16 51. G. Henry and J. Plateau, La Microfractographie, Institute de Recherches de la Sidérurgie Francaise ; see translation by B. Thomas with Preface by C. Crussard, Éditions Métaux  54. The Transmission Electron and Microscope and Its Application to Fractography, in Fractography and Atlas of Fractographs, Vol 9, 8th ed., Metals Handbook, American Society of Metals, 1974, p 54-63 55. V.K. Zworykin and J. Hillier, Microscopy: Electron, Medical Physics, Vol II, 1950, p 511-529 56. J. Hiller, Electron Microscope, in Encyclopedia Britannica, 1960 57. V.E. Cosslett, Practical Electron Microscopy, Academic Press, 1951, p 41-46 58. H. Busch, Calculation of Trajectory of Cathode Rays in Electromagnetic Fields of Axial Symmetry, Ann. d. Physik, Vol 81, 1926, p 59. E. Ruska and M. Knoll, The Electron Microscope, Ztschr. f. Physik, Vol 78, 1932, p 318 60. E. Ruska, Advance in Building and Performing of Magnetic Electron Microscope, Ztschr. f. Physik, Vol, 87, 1934, p 580 61. E. Driest and H.O. Müller, Electron Micrographs of Chitin Substances, Ztschr. f. wissensch. Mikr., Vol 52, 1935, p 53 62. B. von Borries and E. Ruska, Development and Present Efficiency of the Electron Microscope, Wissensch. Veröfent. Siemens-Werke, Vol 17, 1938, p 99 63. A. Prebus and J. Hillier, Construction of Magnetic Electron Microscope of High Resolving Power, Can. J. Res., Vol A17, 1939, p 49 64. A.D. Romig, Jr. et al., Analytical Transmission Electron Microscopy, in Materials Characterization, Vol 10, 9th ed., Metals Handbook, American Society for Metals, 1986, p 429-489 65. L. Robert. J. Bussot, and J. Buzon, First International Congress for Electron Microscopy, Rev. d' Optique, 1953, p 528 66. D.E. Bradley, Br. J. Appl. Phys., Vol 5, 1954, p 96 67. E. Smith and J. Nutting, Br, J. Appl. Phys., Vol 7, 1956, p 214 68. A. Phillips, V. Kerlins, R.A. Rawe and B.V. Whiteson, Ed., Electron Fractography Handbook, sponsored by Air Force Materials Laboratory, Air Force Wright Aeronautical Laboratories, Air Force Systems Command, published by Metals and Ceramics Information Center, Battelle Columbus Laboratories, March 1968 (limited quantities), June 1976 (unlimited distribution) 69. C. Crussard, R. Borione, J. Plateau, Y. Morillon, and F. Maratray, A Study of Impact Test and the Mechanism of Brittle Fracture, J. Iron Steel Inst., Vol 183, June 1956, p 146 70. C. Crussard and R. Tamhankar, High Temperature Deformation of Steels: A Study of Equicohesion, Activation Energies and Structural Modifications, Trans. AIME, Vol 212, 1958, p 718 71. C. Crussard, J. Plateau, R. Tamhankar, and D. Lajeunesse, A Comparison of Ductile and Fatigue Fractures, (Swampscott Conference, 1959), John Wiley & Sons, 1959 72. J. Plateau, G. Henry, and C. Crussard, Quelque Nouvelles Applications de la Microfractographie, Rev.