Dynamic embrittlement
WebSuch kinetics play an important role in the phenomenon of dynamic embrittlement observed in many materials. Calculations of dynamic decohesion have been performed for two mechanisms of impurity supply to the interface: the reaction kinetics and bulk diffusion. In both cases a kinetic parameter R has been identified such that R ≪ 1 for slow ... WebConsidering that the dynamic aging phenomenon and the γ″ precipitation occur concomitantly with the deformation, the results suggest that niobium segregation together with preferential γ″ precipitation at grain boundary and the consequent stress state build up should play also a decisive role in the embrittlement. Exibir menos
Dynamic embrittlement
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WebJun 1, 2008 · Intergranular cracking by dynamic embrittlement: (a) Load relaxation versus time due to cracking of an alloy 718 specimen at T = 650 °C in oxygen showing complete crack stop when evacuating the testing chamber (Ref. ) and (b) schematic representation of the dynamic-embrittlement mechanism WebDynamic embrittlement by impurity segregation is a brittle fracture mode affecting con-taminated polycrystalline materials. The process involves stress-induced diffusion of impurity elements (solutes) along grain boundaries, causing reduction of the grain boundary cohesive energy and eventually intergranular fracture in the material.
WebBoth SAGBO and dynamic embrittlement (or gas phase embrittlement) involve the diffusion of oxygen under stress/strain conditions often within the plastic zone ahead of the crack tip. 37, 40, 46, 47 Accurate measurement of oxygen diffusion ahead of the propagating crack tip is critical to quantitatively describe oxygen-assisted FCP, especially ... WebMar 1, 2005 · The dynamic embrittlement is a time-dependent form of brittle intergranular fracture that occurs in many alloys when stress and elevated temperatures are applied [3, 4]. This phenomenon is due to ...
WebMar 15, 2011 · The phenomenon of dynamic embrittlement involves the stress-induced diffusion of a surface- adsorbed embrittling element into grain boundaries, leading to time-dependent decohesion along these boundaries. Here, the state of our understanding of this generic type of brittle fracture is reviewed, with the focus on cracking of nickel-base ... WebDec 1, 1996 · A precipitation-hardened Cu-0.16%Be alloy is used as a low-temperature model material for dynamic embrittlement, or quasi-static diffusion-controlled intergranular brittle fracture. This alloy is shown to undergo intergranular cracking in air at 150 C and to be almost free of this cracking in 2 {times} 10{sup {minus}6} Torr vacuum at 200 C.
WebMar 9, 2013 · Segregation of secondary element (embrittling) is clearly seen at the grain boundary. EDS was employed to determine the embrittling element, spectra were …
WebMar 24, 2024 · The traditional theory of ductile fracture has limitations for predicting crack generation during a cold shell nosing process. Various damage criteria are employed to explain fracture and failure in the nose part of a cold shell. In this study, differences in microstructure among fractured materials and analysis of their surfaces indicated the … great place to work numeroWebMar 15, 2011 · The phenomenon of dynamic embrittlement involves the stress-induced diffusion of a surface- adsorbed embrittling element into grain boundaries, leading to time … great place to work norwayWebBuilding a resilient workforce. Burnout is a community issue, not an individual one. Through research and initial trials in high stress environments, we are designing tools and … great place to work nederlandWebMay 1, 2011 · Dynamic embrittlement is caused by oxygen diffusion along the grain boundaries, resulting in a time-dependent intergranular decohesion. The result is a fast brittle intercrystalline crack propagation. floor panels that generate electricityWebMar 31, 2015 · Dynamic embrittlement is a fracture process that involves the ingress and diffusion of atomic oxygen to induce time-dependent decohesion of grain boundaries. A … great place to work nyckelfaktorerWebAug 12, 2008 · The mechanism(s) appear to be the same, regardless of whether the embrittlement process is static or dynamic. In many cases, elemental-oxygen diffusion along grain boundaries and subsequent reaction with either second phases at the boundaries or segregated solute appears to be the mechanism leading to brittle GB … floor pan ge dishwasherWebJun 21, 2024 · Material embrittlement can be a result of an enhanced strength and hardness, and a reduced fracture toughness of a material. In fact, material embrittlement occurs in the processes of, for example, machining, projectile penetration, explosion, and tunnel boring, because of the high strain-rates in the processes, as specified in table … floor pan for shower