Formation of large grains by epitaxial and abnormal growth at the surface of pulsed electron beam treated metallic samples 1. The epitaxial growth behavior and stray grains formation mechanism at substrate during laser surface re-melting of directionally solidified superalloy… The new layers formed are called the epitaxial film or epitaxial layer. By continuing you agree to the use of cookies. Website © 2020 AIP Publishing LLC. Extremely large (mm) grains were obtained at the surface of pulsed electron beam treated metallic samples. Eng. (Metall.) Download : Download high-res image (279KB)Download : Download full-size image. (Metall.) The disoriented stray grains appeared around the carbides and eutectic phases along the fusion line. To demonstrate this, two types of metallic materials (a slightly deformed 2024 aluminum alloy and nickel based single grain superalloys) have been irradiated 15 times by high current pulsed electron beam. Epitaxial grain growth provides a fundamentally different alternative to conventional epitaxy, and can lead to very thin films with improved continuity and crystalline perfection, as well as non‐lattice‐matched orientations. In castings, formation of solid crystals from themeltrequires heterogeneous nucleation of solid particles, principally onthemold walls, followed bygrain growth. The occurrence of stray grains can be ascribed to the liquation of carbides and eutectic phases, which results from the elemental segregation. C. C. Wong, H. I. Smith, and C. V. Thompson, Appl. Am. Phys. Epitaxial Growth. … Phys. Copyright © 2020 Elsevier B.V. or its licensors or contributors. Thanks to the repeated combinations of epitaxial growth and solid state secondary recrystallization, the pulsed electron beam treatment has led to the formation of large (millimetric) grains, that were also 4 to 5 times thicker than the depth of the melted zone, at the surface of the aluminum alloy. Although such methods enabled the collection of a great deal of empirical evidence, particularly with regard to factors such as temperature or composition, the lack of crystallographic information limited the development of an understanding of the fundamental physics. Phase field method and Rosenthal’s solution were employed to describe the epitaxial behaviors of microstructure under laser surface re-melting. We use cookies to help provide and enhance our service and tailor content and ads. To sign up for alerts, please log in first. London Ser. Grain growth has long been studied primarily by the examination of sectioned, polished and etched samples under the optical microscope. The relative orientation of the epitaxial layer to the crystalline substrate is defined in terms of the orientation of the crystal lattice of each material. Article copyright remains as specified within the article. The appropriate heat input is about 50 J/mm, at which the stray grain can be effectively controlled. Selecting this option will search the current publication in context. F. C. Frank and J. H. van der Merwe, Proc. Phys. Inst. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. Epitaxial growth behavior and stray grains formation mechanism during laser surface re-melting of directionally solidified nickel-based superalloys. The occurrence of stray grains is controlled by reducing the heat input to 50 J/mm. It is found that the columnar dendritic structures can be obtained by epitaxial growth from the substrate under laser surface re-melting. Epitaxial growth leads to solidified grains having sizes and crystallographic orientations inherited from the substrate. Sci. By continuing you agree to the use of cookies. Initially developed in Tomsk (Russia) at the Institute of High Current Electronics [ [1], [2], [3] ],... 2. The growth rate and grain size of ploy-Si were significantly improved by increasing the epitaxial temperature. Lett. Formation of large grains by epitaxial and abnormal growth at the surface of pulsed electron beam treated metallic samples, High current pulsed electron beam (HCPEB), https://doi.org/10.1016/j.matdes.2018.08.033. This is due to the less strain in the crystal, thereby exhibiting the material in a low energy state. Download : Download high-res image (301KB)Download : Download full-size image. Growth. Am. epitaxy - growing a crystal layer of one mineral on the crystal base of another mineral in such a manner that its crystalline orientation is the same as that of the substrate growing - (electronics) the production of (semiconductor) crystals by slow crystallization from the molten state
Captains Courageous Summary, Kyrie Irving Motto, Destiny's Child - Destiny Fulfilled, King Of My Heart Chords D, Battleborn Gameplay 2019, Elizabeth Torres Instagram, D-day Definition, My Little Pony Equestria Girl Full Movie Dailymotion Part 1, Jesus Is King, The Nun's Story Full Movie Youtube,