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The Effect of Dopants on Structure Formation and Properties of Cast SHS Alloys Based on Nickel Monoaluminide
Alloys based on NiAl-Cr-Co ( ) with complex dopants ( ) were fabricated by centrifugal SHS metallurgy. The phase and impurity compositions, structure, mechanical properties, and the mechanism of high-temperature oxidation at T = 1150 °C were studied; the kinetic oxidation curves, fitting equations a...
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Published in: | Materials 2023-04, Vol.16 (9), p.3299 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Alloys based on NiAl-Cr-Co (
) with complex dopants (
) were fabricated by centrifugal SHS metallurgy. The phase and impurity compositions, structure, mechanical properties, and the mechanism of high-temperature oxidation at T = 1150 °C were studied; the kinetic oxidation curves, fitting equations and parabolic rate constant were plotted. Al
O
and Co
CrO
were the major phases of the oxidized layer. Three layers were formed: I-the continuous Al
O
layer with Co
CrO
inclusions; II-the transitional MeN-Me layer with AlN inclusions; and III-the metal layer with AlN inclusions. The positive effect of thermo-vacuum treatment (TVT) on high-temperature oxidation resistance of the alloy was observed. The total weight gain by the samples after oxidative annealing decreased threefold (from 120 ± 5 g/m
to 40 ± 5 g/m
). The phases containing Ru and Ti microdopants, which reduced the content of dissolved nitrogen and oxygen in the intermetallic phase to the values ∑
= 0.0145 wt.% for the
alloy and ∑
= 0.0223 wt.% for the
alloy, were identified by transmission electron microscopy (TEM). In addition, with the significant high-temperature oxidation resistance, the latter alloy with Ti had the optimal combination of mechanical properties (σ
= 1644 ± 30 MPa; σ
= 1518 ± 25 MPa). |
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ISSN: | 1996-1944 1996-1944 |
DOI: | 10.3390/ma16093299 |