TY - JOUR
T1 - Impact of iron composition on the properties of an additively manufactured solid solution strengthened nickel base alloy
AU - Khayat, Z. R.
AU - Palmer, T. A.
N1 - Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/3/7
Y1 - 2018/3/7
N2 - The impact of changes in Fe content from 1 wt% to 4 wt% on the properties of additively manufactured (AM) Inconel® 625 fabricated using laser-based directed energy deposition (DED) is investigated in both the as deposited and post processed hot isostatically pressed (HIP) conditions. While similar solidification structures and microhardness values are observed, the low Fe content build displayed higher yield (520 MPa ± 12 MPa vs. 450 MPa ± 27 MPa) and tensile strengths (860 MPa ± 27 MPa vs. 753 MPa ± 25 MPa) and lower elongations (36% ± 5% vs. 44% ± 9%) in the as-deposited condition. Differences in mechanical properties are connected to differences in the grain size produced with the different Fe contents. In the as deposited condition, fine grains less than 500 µm in size with low aspect ratios were observed with the low Fe content, while large elongated grains in excess of 1 mm in length were observed with the high Fe content. After HIP, the yield strengths for both Fe contents decreased by 14%, while elongation increased similarly. On the other hand, tensile strengths after post processing changed by only 3%, which were correlated to higher levels of strain hardening for the higher Fe content. These differences in behavior can be attributed, in part, to changes in precipitate morphologies. After HIP post processing, the low Fe content build displayed Nb and Mo rich precipitates, while spherical Ti rich precipitates are present in the high Fe content build.
AB - The impact of changes in Fe content from 1 wt% to 4 wt% on the properties of additively manufactured (AM) Inconel® 625 fabricated using laser-based directed energy deposition (DED) is investigated in both the as deposited and post processed hot isostatically pressed (HIP) conditions. While similar solidification structures and microhardness values are observed, the low Fe content build displayed higher yield (520 MPa ± 12 MPa vs. 450 MPa ± 27 MPa) and tensile strengths (860 MPa ± 27 MPa vs. 753 MPa ± 25 MPa) and lower elongations (36% ± 5% vs. 44% ± 9%) in the as-deposited condition. Differences in mechanical properties are connected to differences in the grain size produced with the different Fe contents. In the as deposited condition, fine grains less than 500 µm in size with low aspect ratios were observed with the low Fe content, while large elongated grains in excess of 1 mm in length were observed with the high Fe content. After HIP, the yield strengths for both Fe contents decreased by 14%, while elongation increased similarly. On the other hand, tensile strengths after post processing changed by only 3%, which were correlated to higher levels of strain hardening for the higher Fe content. These differences in behavior can be attributed, in part, to changes in precipitate morphologies. After HIP post processing, the low Fe content build displayed Nb and Mo rich precipitates, while spherical Ti rich precipitates are present in the high Fe content build.
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U2 - 10.1016/j.msea.2018.01.112
DO - 10.1016/j.msea.2018.01.112
M3 - Article
AN - SCOPUS:85041476374
VL - 718
SP - 123
EP - 134
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
SN - 0921-5093
ER -