Site statistics

34333 facts from 176 countries related to 1175 phenomena have been registered in Archive. 2796 of them were solved, another 10539 are under verification for compliance with one of the 317 versions.

18 facts have been added for last 24 hours.

Share your story

You are in "Versions" section

This section includes information about possible versions explaining the true nature of the event described in the fact.

Видманштеттенова структура

Added Tue, 15/10/2019
Sources
Феномены
Version type

Widmanstatten structure or structure Thomson - a kind of metallographic structure of alloys in metallurgy and meteoritika, wherein the geometrically correct arrangement of the structure elements in the form of plates, polygons, or needles inside the components of the alloy crystal grains.

This term was used to refer to shapes or patterns occurs when the cut and etched with acid, most iron meteorites. Such a pattern arises, if at low temperatures of space two crystallizing mineral cannot be mixed. Attempts to create widmanstatten figures in laboratory conditions fail.

It looks like the structure of the iron meteorites (octahedrites), revealed by etching polished surfaces of the samples.

Widmanstatten shapes are formed by a system of parallel plates (beams): kamacite, regularly arranged parallel to the octahedron faces. Iron meteorites contain four such plates, the intersection of which with each other form a complex morphological pattern. Capacitive beams fringed with thin slices Tanita; the residual space between the beams is made of fine-grained mixture: kamacite and Tanita (plessite).

Appearance widmanstatten figures is primarily attributed to the extremely slow subsolidus cooling high-temperature originally homogeneous iron-Nickel phase. High-temperature face-centered modification of y-Fe, as well as poor Nickel it difference, when cooling it goes into a stable modification of a-Fe with body-centered lattice, whereas Ni-rich difference retain the face-centered lattice.

Significant Nickel content in the cooling system causes two-phase region, which expands with decreasing temperature; thus the a-phase precipitates mainly along the octahedral planes of the phases. Thus, the cooling process leads to disintegration of high-temperature Ni-Fe solid solution, which is the direct cause of widmanstatten figures.

Translated by «Yandex.Translator»


Log in or register to post comments

Site friends

  • Мир тайн — сайт о таинственном
  • Activite-Paranormale
  • UFOlats
  • Новый Бестиарий
  • The Field Reports
  • UFO Meldpunt Nederland
  • GRUPO DE ESTUDOS DE UFOLOGIA CIENTÍFICA
  • Паранормальная наука, наука об аномалиях
  • Новости уфологии
  • UFO Insights
  • Mundo Ovnis

Attention!

18+

Site contains materials that are not recommended for impressionable people.

You are reporting a typo in the following text:
Simply click the "Send typo report" button to complete the report. You can also include a comment.