13th International Conference on Fracture June 16–21, 2013, Beijing, China -2- and a metal slice is formed on the powder bed. a) b) c) d) e) f) I II III Figure 1. Schematic description of the SLM process. a) Powder is distributed on a powder bed, the build platform. b) The powder is melted by a laser beam and a slice of solid metal is formed. c) The powder bed is lowered and the process is repeated until a finished component is formed. I: A powder distributer travels over the powder bed cavity contained by the build chamber walls b) and build plate c). Molten and solidified powder constitutes the component d) surrounded by unmolten powder e). II: A laser beam f) melts the powder layer and creates a new slice of solid material in the component d). III: A ram lowers the build platform c) and the process is repeated until a finished geometry is formed. After finalization, the remaining loose powder is removed and the component is cut off from the build platform. 2. Experimental details 2.1. Material In the current work, material in principle conforming to AMS 5754 / UNS N06002 (i.e. Hastelloy X from Haynes International) has been used. In literature the material is sometimes identified as “Alloy X” when not available from the original supplier. The powder material is gas atomized and sieved to a fraction suitable for the SLM process, Figure 2. Solid test bars, hollow specimens and lattice truss structures with diamond geometry, Figure 3, were produced in an Eosint M270 DM machine. After manufacturing no heat treatment was adopted. In Table 1, the nominal composition of Hastelloy X is shown. The typical microstructure of the SLM material after manufacturing is shown below, Figure 4.
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