FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W3136136175> ?p ?o ?g. }

• W3136136175 abstract "The combination of mechanical properties, corrosion resistance and low neutron absorption cross section makes zirconium-based alloys very important structural materials in the nuclear industry. To maintain functionality of zirconium alloys in nuclear environments, it is important to understand effects of alloying elements and elements resulting from fission, transmutation, and coolant interactions on material properties. Of particular concern is weakening caused by accumulation of impurities at grain boundaries. Resistance of zirconium-based alloys to radiation embrittlement is highly valued in reactor design. Even after significant irradiation, Zircaloy fracture surfaces exhibit ductile fracture features. However, during power transients in commercial nuclear power plants, brittle fracture can occur and is known as pellet-clad interaction (PCI). The responsible mechanism is believed to be fission product induced stress corrosion cracking, with iodine suspected as the primary detrimental specie. However, mechanistic details for how iodine promotes brittle failure are not well understood, with two main mechanisms proposed. One mechanism involves iodine being adsorbed on a crack face lowering Zr-Zr bond energies, leading to separation along crystallographic planes (transgranular cleavage crack path) or grain boundaries (intergranular crack path). Another mechanism postulates that crack advance occurs by formation of Zrl{sub 4}(g) which transports Zr away from crack tips. The importance of iodine concentration and Zrl{sub 4} partial pressure on SCC (stress corrosion cracking) susceptibility of Zircaloy has been shown in several studies. While it is difficult to obtain experimental information on effects of impurity atoms on grain boundary (GB) strength, first-principles calculations can provide insight. This work first studied the effect of twenty impurity and alloy elements on the strength of a Zr(0001)/ Zr(0001) {sigma}7 twist grain boundary. Modeling based on ab initio density functional theory (DFT) was used for all calculations as implemented in the Vienna ab initio Simulation Package (VASP). For each impurity investigated the preferred occupancy site (substitutional, interstitial, or surface adatom), segregation energy (from bulk to surface or grain boundary), and change in Zr grain boundary cohesion energy were calculated. The influence of twenty different impurity elements on the Zr grain boundary work of separation was ranked in order of most weakening to most strengthening: Cs, I, He, Te, Sb, Li, Sn, Cd, O, H, Si, C, N, U, B, Ni, Hf, Nb, Cr, and Fe. These results demonstrate that strength of a Zr {sigma}7 (0001) twist grain boundary is quite insensitive to most impurity elements. In part, this is due to similar behavior of impurities at grain boundaries and at free Zr surfaces. Elements that prefer a substitutional site in bulk Zr also prefer substitutional sites at surfaces and in Zr {sigma}7 (0001) grain boundaries, Exceptions are Li, I, and s, that prefer bulk substitutional sites but prefer an adatom position at free surfaces (He which just leaves free surfaces is another exception). These elements are also among those with the largest reduction in calculated grain boundary cohesion. No element in this study showed a large beneficial effect on grain boundary strength. Comparison of modeling and experimental reports reveals consistency for iodine embrittlement results. Both computations and experiments show iodine to weaken grain boundaries, however, results for Cs and He are inconsistent between modeling and literature. Experimentally He does not promote brittle failure, and is readily understood as there is no driving force for helium to interact with zirconium. For Cs, neither brittle intergranular nor transgranular cleavage was reported even though calculations show Cs to be the most embrittling for a Zr {sigma}7 (0001) grain boundary. This may be attributed to details of failure mechanisms that have not yet been explored, such as how detrimental elements interact at a crack tip to lower strength of a boundary and enhance kinetic transport phenomena. To further investigate kinetics of detrimental effects of iodine on Zr cohesion, adsorption, dissociation, and diffusion of iodine on a Zr surface were studied using a first-principles approach. Different static and dynamic simulations were run for adsorption and dissociation of molecular iodine on a Zr(0001) surface. Molecular iodine (I{sub 2}) impinging on a Zr (0001) surface shows no barrier to surface approach and no precursor state, resulting in spontaneous dissociation of 12 molecules on this surface. The equilibrium surface coverage of iodine atoms on zirconium was calculated as a function of temperature and partial pressure of molecular iodine in the gas phase. Computed adsorption isotherms show significant adsorption site occupancy even at extremely low I{sub 2} partial pressures. Diffusion of iodine atoms on a Zr (0001) surface was calculated by considering jumps between stable FCC sites. Tracing an energy profile along a diffusion path shows minima exist at FCC sites and local minima occur at HCP sites. A diffusion coefficient for iodine can be expressed using an Arrhenius relationship as D = D{sub o}e{sup -Q/RT} with Q = 6.77 kJ/mol and 2.0 x 10{sup -4} cm{sup 2}/sec. Diffusion of iodine atoms on a Zr surface was calculated to be quite fast with little activation energy required. These results indicate that iodine, which is shown computationally and experimentally to be detrimental to Zr, has a high tendency to react with a zirconium surface and a high mobility once dissociated on a surface. These behaviors support an iodine-enabled Zr cracking mechanism. (authors)" @default.
• W3136136175 created "2021-03-29" @default.
• W3136136175 creator A5006192101 @default.
• W3136136175 creator A5006500928 @default.
• W3136136175 creator A5033811462 @default.
• W3136136175 creator A5033867554 @default.
• W3136136175 creator A5040710513 @default.
• W3136136175 creator A5066995257 @default.
• W3136136175 date "2009-06-01" @default.
• W3136136175 modified "2023-09-25" @default.
• W3136136175 title "Effect of impurity and Alloying Elements on Zirconium (Zr) Grain Boundary Strength and Iodine Adsorption, Dissociation, and Diffusion from First-Principles Computations" @default.
• W3136136175 hasPublicationYear "2009" @default.
• W3136136175 type Work @default.
• W3136136175 sameAs 3136136175 @default.
• W3136136175 citedByCount "0" @default.
• W3136136175 crossrefType "journal-article" @default.
• W3136136175 hasAuthorship W3136136175A5006192101 @default.
• W3136136175 hasAuthorship W3136136175A5006500928 @default.
• W3136136175 hasAuthorship W3136136175A5033811462 @default.
• W3136136175 hasAuthorship W3136136175A5033867554 @default.
• W3136136175 hasAuthorship W3136136175A5040710513 @default.
• W3136136175 hasAuthorship W3136136175A5066995257 @default.
• W3136136175 hasConcept C110419238 @default.
• W3136136175 hasConcept C136478896 @default.
• W3136136175 hasConcept C142282041 @default.
• W3136136175 hasConcept C184102282 @default.
• W3136136175 hasConcept C191897082 @default.
• W3136136175 hasConcept C192562407 @default.
• W3136136175 hasConcept C20625102 @default.
• W3136136175 hasConcept C2778760603 @default.
• W3136136175 hasConcept C34425451 @default.
• W3136136175 hasConcept C47908070 @default.
• W3136136175 hasConcept C534791751 @default.
• W3136136175 hasConcept C87976508 @default.
• W3136136175 hasConceptScore W3136136175C110419238 @default.
• W3136136175 hasConceptScore W3136136175C136478896 @default.
• W3136136175 hasConceptScore W3136136175C142282041 @default.
• W3136136175 hasConceptScore W3136136175C184102282 @default.
• W3136136175 hasConceptScore W3136136175C191897082 @default.
• W3136136175 hasConceptScore W3136136175C192562407 @default.
• W3136136175 hasConceptScore W3136136175C20625102 @default.
• W3136136175 hasConceptScore W3136136175C2778760603 @default.
• W3136136175 hasConceptScore W3136136175C34425451 @default.
• W3136136175 hasConceptScore W3136136175C47908070 @default.
• W3136136175 hasConceptScore W3136136175C534791751 @default.
• W3136136175 hasConceptScore W3136136175C87976508 @default.
• W3136136175 hasLocation W31361361751 @default.
• W3136136175 hasOpenAccess W3136136175 @default.
• W3136136175 hasPrimaryLocation W31361361751 @default.
• W3136136175 hasRelatedWork W1968003658 @default.
• W3136136175 hasRelatedWork W1987732745 @default.
• W3136136175 hasRelatedWork W1987986500 @default.
• W3136136175 hasRelatedWork W1992902276 @default.
• W3136136175 hasRelatedWork W1993468383 @default.
• W3136136175 hasRelatedWork W2024395815 @default.
• W3136136175 hasRelatedWork W2063705609 @default.
• W3136136175 hasRelatedWork W2087997832 @default.
• W3136136175 hasRelatedWork W2233302583 @default.
• W3136136175 hasRelatedWork W2405641674 @default.
• W3136136175 hasRelatedWork W2530603866 @default.
• W3136136175 hasRelatedWork W2800667007 @default.
• W3136136175 hasRelatedWork W2903432319 @default.
• W3136136175 hasRelatedWork W2912487359 @default.
• W3136136175 hasRelatedWork W3046847308 @default.
• W3136136175 hasRelatedWork W3084674277 @default.
• W3136136175 hasRelatedWork W3100549356 @default.
• W3136136175 hasRelatedWork W3131802875 @default.
• W3136136175 hasRelatedWork W3179658386 @default.
• W3136136175 hasRelatedWork W410789874 @default.
• W3136136175 isParatext "false" @default.
• W3136136175 isRetracted "false" @default.
• W3136136175 magId "3136136175" @default.
• W3136136175 workType "article" @default.