Production and Properties of Amorphous Layers on Metal Substrates by Laser and Electron Beam Melting

1981 ◽  
Vol 8 ◽  
Author(s):  
H.W. Bergmann ◽  
B.L. Mordike
Keyword(s):  
Electron Beam ◽  
Laser Beam ◽  
Single Crystals ◽  
Electron Beam Melting ◽  
Cold Working ◽  
Amorphous Layer ◽  
Laser Glazing ◽  
Surface Layers ◽  
Metal Substrates ◽  
Amorphous Surface

ABSTRACTVarious techniques of laser glazing are presented. Rules are given for the choise of systems which are suitable for producing amorphous surface layers. Methods of demonstrating the existence of a truly amorphous layer are discussed. Two examples are given: I) electron beam glazing of Ni-Nb coated single crystals 2) laser beam glazing of Fe-B coated Fe-Cr-C cold working steel.

Laser Quenching of Amorphous Si from the Melt Containing Dopants

1983 ◽  
Vol 23 ◽  
Author(s):  
S. U. Campisano ◽  
D. C. Jacobson ◽  
J. M. Poate ◽  
A. G. Cullis ◽  
N. G. Chew
Keyword(s):  
Laser Irradiation ◽  
Ruby Laser ◽  
Metal Layer ◽  
Amorphous Layer ◽  
Irradiation Condition ◽  
Uv Laser ◽  
Surface Layers ◽  
Interfacial Segregation ◽  
Amorphous Si ◽  
Amorphous Surface

ABSTRACTThe formation of amorphous Si by the quench of a thin surface layer melted by fast UV laser irradiation has been investigated. The starting (111) surface layers were either pure or doped with As, Bi, In and Te by implantation. The asimplanted samples were recrystallized by ruby laser irradiation resulting in surface accumulation of Bi,In and Te. For the same UV irradiation condition, the amorphous layer formed in As, Bi, In or Te doped Si is about twice the thickness of the amorphous layer formed on pure Si. In the presence of the surface accumulation of Bi, In or Te, the amorphization results in an inward segregation of the dopant. For In, a very thin metal layer ˜15Å thick, is formed 150Å beneath the amorphous surface. These results show that the amorphous-liquid interfacial segregation coefficients for Bi, In or Te are less than unity and that the amorphous solidification proceeds from the surface and bottom of the liquid layer.

scholarly journals Fabrication of Single Crystals through a µ-Helix Grain Selection Process during Electron Beam Metal Additive Manufacturing

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 313 ◽  
Author(s):  
Martin R. Gotterbarm ◽  
Alexander M. Rausch ◽  
Carolin Körner
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Single Crystals ◽  
Electron Beam Melting ◽  
Selection Process ◽  
Powder Bed ◽  
Grain Structures ◽  
Selective Electron Beam Melting ◽  
Columnar Grain ◽  
Metal Additive

Selective Electron Beam Melting (SEBM) is a powder bed-based additive manufacturing process for metals. As the electron beam can be moved inertia-free by electromagnetic lenses, the solidification conditions can be deliberately adjusted within the process. This enables control over the local solidification conditions. SEBM typically leads to columnar grain structures. Based on numerical simulation, we demonstrated how technical single crystals develop in IN718 by forcing the temperature gradient along a µ-Helix. The slope of the µ-Helix, i.e., the deviation of the thermal gradient from the build direction, determined the effectiveness of grain selection right up to single crystals.

Ion Channeling Studies of Crystallinity, Amorphization, and Thermal Annealing in Single-Crystal YBa2Cu3Ox.

1987 ◽  
Vol 99 ◽  
Author(s):  
N. G. Stoffel ◽  
W. A. Bonner ◽  
P. A. Morris ◽  
B. J. Wilkens
Keyword(s):  
Single Crystals ◽  
High Temperature Superconductor ◽  
Solid Phase ◽  
Amorphous Layer ◽  
Surface Layers ◽  
Ion Channeling ◽  
Oxygen Ion ◽  
Surface Disorder ◽  
Axial Channeling ◽  
Oxygen Ion Implantation

ABSTRACTWe have performed Rutherford backscattering spectroscopy (RBS) and axial channeling on single crystals of the high-temperature superconductor YBa2Cu3Ox. The results demonstrate good crystal quality and cation stoichiometry in the as-grown samples. We observe some surface disorder, and estimate from the surface-peak intensities that there is roughly one formula unit of misregistered atoms per unit cell, or one molecular monolayer of surface disorder.We have studied the surface disorder induced in these crystals by various surface processing treatments, and have tried to achieve solid-phase epitaxial regrowth of disordered surface layers. Preliminary results have been obtained on the annealing of 100 nm amorphous layers formed on the surface of single crystals by 30 keV oxygen ion implantation. The Ba in the amorphous layer was found to segregate strongly to the surface for annealing temperatures as low as 500°C, although the crystalline phase does not decompose even at much higher temperatures.

Furnace Anneal of A–Axis Sapphire Amorphised by Indium Ion Implantation

1988 ◽  
Vol 128 ◽  
Author(s):  
D. K. Sood ◽  
D. X. Cao
Keyword(s):  
Activation Energy ◽  
Ion Implantation ◽  
Amorphous Phase ◽  
Isothermal Annealing ◽  
Amorphous Layer ◽  
Surface Layers ◽  
Epitaxial Regrowth ◽  
Rapid Diffusion ◽  
Amorphous Surface ◽  
Higher Doses

ABSTRACTIndium implantation at 77°K into a–axis sapphire to peak concentrations of 6–45 mol % In produces amorphous surface layers. Isothermal annealing in Ar at temperatures between 600–900°C shows effects strongly dependent on ion dose. At lower doses <2×1016 In/cm2, the amorphous layer undergoes epitaxial regrowth as the amorphous to crystalline interface advances out towards the surface. Regrowth velocity is high in about the first half hour of the anneal. Regrowth obeys Arrhenius behaviour with an activation energy of 0.7eV for initial faster growth and 1.28eV for further anneal times. The amorphous phase transforms directly to ⊥-A12O3 without any evidence of an intermediary γ-phase. At higher doses, epitaxial regrowth is substantially retarded and rapid diffusion of In within the amorphous phase dominates.

scholarly journals Comparative Analysis of the Oxygen Supply and Viability of Human Osteoblasts in Three-Dimensional Titanium Scaffolds Produced by Laser-Beam or Electron-Beam Melting

Materials ◽  
2013 ◽  
Vol 6 (11) ◽  
pp. 5398-5409 ◽  
Author(s):  
Anika Jonitz-Heincke ◽  
Jan Wieding ◽  
Christoph Schulze ◽  
Doris Hansmann ◽  
Rainer Bader
Keyword(s):  
Electron Beam ◽  
Comparative Analysis ◽  
Laser Beam ◽  
Electron Beam Melting ◽  
Oxygen Supply ◽  
Three Dimensional ◽  
Human Osteoblasts
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