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, the effects of fiber composition, size, and surface treatment on the mechanical behavior of slip-cast fused-silica composites were investigated, and the ambient and 1000°C stiffness and strength, fracture toughness, GR -curve behavior, and fiber-matrix interface bond strength were determined.
Abstract: The effects of fiber composition, size, and surface treatment on the mechanical behavior of slip-cast fused-silica composites were investigated. The ambient and 1000°C stiffness and strength, fracture toughness, GR -curve behavior, and fiber-matrix interface bond strength were determined. Quantitative fractography and scanning electron microscopy were used to ascertain the mechanisms of toughening and strengthening. Composites with weak interface bonding exhibited good strength retention and rising GR -curve behavior. The fracture resistance was improved primarily through crack deflection.
58 citations
TL;DR: In this paper, the multistage fatigue model developed by McDowell et al. was modified to study the fatigue life of a magnesium alloy AE44 for automobile applications, and fractographic examination indicated three distinct stages of fatigue damage in the high cycle fatigue loading regime: crack incubation, microstructurally small crack growth, and long crack growth.
58 citations
TL;DR: In this paper, a thermal model was developed and applied to simulate the friction stir welding of pure copper plates with the thickness of 2 mm and different traverse speeds of 100, 200, 300, and 400 mm min−1 and rotational speeds of 400, 700, 900, and 900 rev−1 were considered as welding parameters.
Abstract: In this study, a thermal model was developed and applied to simulate the friction stir welding of pure copper plates with the thickness of 2 mm. The different traverse speeds of 100, 200, 300, and 400 mm min−1 and rotational speeds of 400, 700, 900 rev min−1 were considered as welding parameters. Microstructural characterization, hardness measurement, tensile test, and fractography were conducted experimentally. The comparison between the numerical and experimental results showed that the developed model was practically accurate. In addition, the results confirmed that the peak temperature was the dominant factor controlling the grain size and mechanical properties, where the fine grains could be achieved at low rotational speed as well as high traverse speed. Consequently, lower peak temperature leads to the high ultimate tensile strength and hardness and the low elongation values.
58 citations
TL;DR: A series of laminated Ti-(TiBw/Ti) composites fabricated at different diffusion welding temperatures of 1100, 1200, and 1300°C were subjected to tensile and bending tests as discussed by the authors.
Abstract: A series of laminated Ti-(TiBw/Ti) composites fabricated at different diffusion welding temperatures of 1100 °C, 1200 °C and 1300 °C were subjected to tensile and bending tests. The results showed that the interfacial bonding strength, interfacial toughness and residual stress gradually increased with the increasing fabrication temperature. Therefore, along the transversal direction, the laminated composites fabricated at 1300 °C revealed the highest tensile strength and fracture elongation. However, the highest tensile strength (694 MPa) and elongation (22.7%) along the longitudinal direction, was recorded with the laminated composites fabricated at 1200 °C due to reasonable interfacial bonding and residual stress. Interestingly, the laminated composites fabricated at 1100 °C exhibited the highest bending fracture toughness and fracture work along arrester orientation. Due to the weak interfaces, the crack propagation path was displaced by delamination cracks and re-nucleated multiple tunnel cracks, which in turn lead to reduction in stress intensity of the main crack. This was beneficial to the toughening of the laminated Ti-(TiBw/Ti) composites.
58 citations
TL;DR: A study of crack growth in vacuum and air at 725 °C (T/T m=06) highlights the relative importance of creep and environmental crack-tip damage mechanisms in powder Metallurgy (P/M) disc alloy RR1000.
Abstract: A study of crack growth in vacuum and air at 725 °C (T/T
m=06) highlights the relative importance of creep and environmental crack-tip damage mechanisms in Powder Metallurgy (P/M) disc alloy RR1000 Both of these mechanisms are associated with a transition to intergranular fracture during fatigue crack growth at 025 Hz Crack growth under sustained loads reveals the precise nature of these mechanisms in RR1000 The severity of creep and environmental mechanisms is controlled by the grain-boundary microstructure and the crack-tip stress Near-tip cavitation leads to fracture in vacuum Sigma-phase precipitation causes an increase in crack growth rate through increased crack-tip cavity nucleation Rapid near-tip stress relaxation induced by γ′ coarsening has a beneficial effect on the severity of this type of damage In air, increases in crack growth rates are associated with near-tip intergranular oxidation It is proposed that the extent of this damage and subsequent growth rates are increased by sigma-phase precipitation through enhanced oxidation due to chromium depletion and subsequent decreased passivation Again, a beneficial effect of rapid near-tip stress relaxation due to selective γ′ coarsening is apparent and environmental damage is reduced under these conditions
58 citations