Topic
Fractography
About: Fractography is a research topic. Over the lifetime, 5043 publications have been published within this topic receiving 86068 citations.
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TL;DR: In this paper, a study of the long and small fatigue crack growth behavior in IN100 tested at 650°C both with and without dwell periods is summarized, and it is observed that the influence of loading variables on small crack behavior is profoundly different from that on long cracks.
37 citations
TL;DR: In this paper, the authors investigated the fracture toughness of fiber metal laminates (FMLs) and found that the Mode I interlaminar toughness (0.23kJ/m2) of the FMLs is much lower than the Mode II interlaminar toughness (5.81kJ /m2), due to the fact that the effects of mechanical interlock to hinder crack propagation is smaller under Mode I loading conditions than under Mode II.
Abstract: The fiber metal laminates (FML), consisting of carbon fiber reinforced polymer prepregs and magnesium alloys sheets, were introduced, and the Mode I (peel) and Mode II (shear) interlaminar fracture toughness of the FMLs were investigated. The results show that the Mode I interlaminar toughness (0.23 kJ/m2) of the FMLs is much lower than the Mode II interlaminar toughness (5.81 kJ/m2), due to the fact that the effects of mechanical interlock to hinder crack propagates is smaller under Mode I loading conditions than under Mode II. The FMLs mainly show adhesive failure and interfacial failure under Mode I loading conditions, while for Mode II loading, it exhibits a degree of epoxy cohesive failure except the adhesive failure and interfacial failure.
37 citations
TL;DR: In this article, the authors introduced the profile and surface roughness parameters, which are required to transform measurements made on flat SEM fractographs to the true quantities in the fracture surface.
Abstract: The important aspects of quantitative fractography as a new analytical tool for understanding material fracture are discussed. The special considerations that rise in the quantification problems are examined from the purview of stereology. Two major experimental techniques for obtaining geometrical information about the fracture surface topography are critically evaluated. These methods are based on stereophotogrammetry or vertical sectioning procedures-both of which yield estimates of the true fracture surface area. The profile and surface roughness parameters which are required to transform measurements made on flat SEM fractographs to the true quantities in the fracture surface are introduced. The two roughness parameters are related by a simple parametric equation, permitting the fracture surface area to be calculated from the experimental measurement of the profile roughness parameter. Alternatively, it is shown how the fracture surface area can be obtained from the angular distribution of the profile elements by employing a transform procedure. The concept of “fractals” as it applies to quantitative fractography is introduced. Recently developed relationships which describe the true variation of the profile and surface roughness parameters with the size of the measuring unit are presented. Calculations are made of the mean area and perimeter length of dimples in the fracture surface of a 4340 steel. Three fracture surface configurations are examined: (1) an assumed flat- , (2) an assumed randomly-oriented- , and (3) the actual partially-oriented fracture surface. Significant differences are demonstrated between the true and the assumed situations, illustrating the importance of quantitative methods in fractography. By means of examples, it is shown how the quantitative methods permit detection of subtle changes in the fracture surface topography as influenced by the materials’ microstructure.
37 citations
TL;DR: In this article, the fatigue crack response in the accelerated crack propagation range can adequately be described by the Paris equation and the onset of stable crack propagation acceleration occurred above a characteristics threshold stress intensity factor (ΔKt) which separates the accelerated from that of the delayed stable crack growth region.
37 citations
TL;DR: In this paper, accumulative extrusion bonding (AEB) was used to refine grain and improve mechanical properties of aluminum specimens, and the results showed that the strength reached the maximum value of 195 MPa and the total elongation exceeded 16% after five passes.
37 citations