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Determination of the order in the intermetallic phase Ni 3 Al as a function of temperature
Author(s) -
Stoeckinger G. R.,
Neumann J. P.
Publication year - 1970
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889870005605
Subject(s) - intermetallic , diffractometer , atmospheric temperature range , stoichiometry , debye model , melting point , alloy , phase (matter) , materials science , aluminium , analytical chemistry (journal) , thermodynamics , chemistry , crystallography , crystal structure , metallurgy , composite material , physics , organic chemistry , chromatography
The degree of long range order in the γ′‐phase of the nickel–aluminum system was determined as a function of temperature by means of X‐rays. The measurements were carried out on { h 00} single crystals, using a high‐temperature vacuum X‐ray diffractometer. Two compositions were investigated: stoichiometric Ni 3 Al and an off‐stoichiometric nickel‐rich alloy. Complete long‐range order was present to within 65°C of the melting point, the highest temperature measured. Line breadth measurements indicated a large, temperature independent anti‐phase domain size. From the intensity variation of the 400 reflection with temperature, a Debye temperature of 360°K was deduced. The linear coefficient of thermal expansion between 25 and 800°C was found to be 15 x 10 −6 per °C.