conditions. Material should be analyzed (see Fig. ID) Artifacts(tire tracks) Common in cyclic loading Due to entrapped particulate matter Reference cited in this section Microelectronic Failure Analysis Desk Reference, 4th ed, R.J. Ross and C. Boit, Ed, ASM International. 1999 Fracture Appearance and Mechanisms of Deformation and fracture W.T. Becker, University of Tennessee, Emeritus; S. Lampman, ASM International General Background on Fractography Fractography is an active research area and has benefited from a closely related interest in quantitative assessment of load carrying capability as predicted by fracture mechanics(and vice versa). The coupling probably first became obvious when Griffith's model for brittle fracture was applied to the study of cleavage fracture in metallic materials in 1954. It was then realized that cleavage fracture in crystalline materials could not be based simply on a normal stress criterion(e.g, see Honeycombe(Ref 2) Many new tools and techniques for studying fracture surfaces have become available and made possible a more omplete understanding of fracture processes. A 1948 fracture text and symposium(Ref 3) focused heavily on macroscale phenomenological mechanics and multiaxial"failure"surfaces. An important conference on fracture held in 1959(Ref 4) included no fractographs using an electron beam for illumination. A subsequently published conference proceedings on fracture in 1962(Ref 5)contained only a few electron fractographs The rapid development of both the transmission electron microscope(TEM) and soon after, the scanning electron microscope(SEM)during the 1960s provided new and very powerful tools to examine fracture surfaces with significantly improved resolution and depth of field. The TEM was available first, and most of the early fractographs were obtained with the TEM. These replicas are reversed images of the fracture surface. The differences in appearance between fractographs obtained from replicas and by direct observation can also be striking. Because of the early use of the TEM in microfractography, a substantial amount of fractographic images via TEM replicas have been published. In 1966, for example, Cedric Beachem published the results of an extensive study of fractographic features and interpretation at the Naval Research Laboratory(Ref 6). This report also contains a detailed discussion of artifacts that can be created by replication of the fracture surface and handling of the replie Reference 6 was soon followed by an ASTM Symposium on Electron Fractography in 1967(Ref 7). At essentially the same time, La Microfractographie was published in France(Ref 8). In 1971, a second ASTM book(Ref 9)was published, followed in 1975 by second major compilation of fractographic information(Ref 10), which contained extensive direct SEM images of the fracture surface. The use of sEM had advantages over TEM. The availability of the SEM obviated the necessity of replicating the fracture surface for examination and also provided the capability to examine larger areas of the fracture surface but at decreased resolution. The ability to place large sections in the microscope is of considerable importance, because incomplete examination of the fracture surface may result in not obtaining critical information. The correct procedure is to document the fracture surface in a series of photographs obtained at increasing magnification, each time indicating the region of the higher magnification in the previous photograph. This is not easy to do using the TEM for examination due to the size limitation of the replica(approximately 3. 2 to 6.4 mm, or to in., in diameter) Since the 1970s, the sem has become the most common instrument of use for high-magnification examination of the fracture surface today(variable pressure SEM for polymeric materials). Optical light fractography is stillconditions. Material should be analyzed (see Fig. 11) Artifacts (tire tracks) · Common in cyclic loading · Due to entrapped particulate matter Reference cited in this section 1. Microelectronic Failure Analysis Desk Reference, 4th ed., R.J. Ross and C. Boit, Ed., ASM International, 1999 Fracture Appearance and Mechanisms of Deformation and Fracture W.T. Becker, University of Tennessee, Emeritus; S. Lampman, ASM International General Background on Fractography Fractography is an active research area and has benefited from a closely related interest in quantitative assessment of load carrying capability as predicted by fracture mechanics (and vice versa). The coupling probably first became obvious when Griffith's model for brittle fracture was applied to the study of cleavage fracture in metallic materials in 1954. It was then realized that cleavage fracture in crystalline materials could not be based simply on a normal stress criterion (e.g., see Honeycombe (Ref 2). Many new tools and techniques for studying fracture surfaces have become available and made possible a more complete understanding of fracture processes. A 1948 fracture text and symposium (Ref 3) focused heavily on macroscale phenomenological mechanics and multiaxial “failure” surfaces. An important conference on fracture held in 1959 (Ref 4) included no fractographs using an electron beam for illumination. A subsequently published conference proceedings on fracture in 1962 (Ref 5) contained only a few electron fractographs. The rapid development of both the transmission electron microscope (TEM) and soon after, the scanning electron microscope (SEM) during the 1960s provided new and very powerful tools to examine fracture surfaces with significantly improved resolution and depth of field. The TEM was available first, and most of the early fractographs were obtained with the TEM. These replicas are reversed images of the fracture surface. The differences in appearance between fractographs obtained from replicas and by direct observation can also be striking. Because of the early use of the TEM in microfractography, a substantial amount of fractographic images via TEM replicas have been published. In 1966, for example, Cedric Beachem published the results of an extensive study of fractographic features and interpretation at the Naval Research Laboratory (Ref 6). This report also contains a detailed discussion of artifacts that can be created by replication of the fracture surface and handling of the replica. Reference 6 was soon followed by an ASTM Symposium on Electron Fractography in 1967 (Ref 7). At essentially the same time, La Microfractographie was published in France (Ref 8). In 1971, a second ASTM book (Ref 9) was published, followed in 1975 by second major compilation of fractographic information (Ref 10), which contained extensive direct SEM images of the fracture surface. The use of SEM had advantages over TEM. The availability of the SEM obviated the necessity of replicating the fracture surface for examination and also provided the capability to examine larger areas of the fracture surface but at decreased resolution. The ability to place large sections in the microscope is of considerable importance, because incomplete examination of the fracture surface may result in not obtaining critical information. The correct procedure is to document the fracture surface in a series of photographs obtained at increasing magnification, each time indicating the region of the higher magnification in the previous photograph. This is not easy to do using the TEM for examination due to the size limitation of the replica (approximately 3.2 to 6.4 mm, or 1 8 to 1 4 in., in diameter.) Since the 1970s, the SEM has become the most common instrument of use for high-magnification examination of the fracture surface today (variable pressure SEM for polymeric materials). Optical light fractography is still