CPC B29C 64/153 (2017.08) [B22F 10/28 (2021.01); B22F 10/38 (2021.01); B22F 10/50 (2021.01); B29C 64/268 (2017.08); B33Y 70/00 (2014.12); H01F 1/0311 (2013.01); B22F 10/32 (2021.01); B22F 10/62 (2021.01); B22F 12/70 (2021.01); B33Y 80/00 (2014.12); C01B 21/0622 (2013.01)] | 19 Claims |
1. A method of manufacturing a three-dimensional object using a powder bed fusion additive manufacturing technique, the method comprising:
(a) providing a powder feed material including an alloy of iron (Fe) and carbon (C);
(b) distributing a layer of the powder feed material over a solid substrate;
(c) scanning selective regions of the layer of the powder feed material with a laser beam to locally melt the selective regions and form a pool of molten feed material, the selective regions of the layer corresponding to a cross-section of a three-dimensional object being formed;
(d) exposing the pool of molten feed material to gaseous carbon and gaseous nitrogen to dissolve carbide ions and nitride ions into the pool of molten feed material to produce a molten carbon and nitrogen-containing solution;
(e) terminating the laser beam to cool and solidify the molten carbon-containing solution into a solid layer of hardened steel; and
(f) repeating steps (b) through (e) to form a three-dimensional object made up of a plurality of solid layers of hardened steel,
wherein the plurality of solid layers of hardened steel comprise, by weight, 0.1% to 4% carbon and 0.01% to 0.5% nitrogen, and
wherein the plurality of solid layers of hardened steel exhibit a body-centered cubic crystal structure or a face-centered cubic crystal structure.
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