13th International Conference on Fracture June 16–21, 2013, Beijing, China -4- 10-45µm. The nominal composition of Hastelloy X is shown below as reference, Table 1. Table 1. Nominal composition of Hastelloy X hot-rolled material. Ni Cr Fe Mo Co Si Mn W Bal. 22 18 9 1.5 <1 <1 0.6 During SLM manufacturing the material is built up layer-wise with a layer thickness of 20µm. The typical powder morphology is shown below, Figure 3. The material is well atomized without large amounts of satellites, fused/bonded particles or inhomogenities. Figure 3. Scanning electron microscopy image of recycled Alloy X powder morphology. The powder is relatively free from satellites and sintered/bonded particles. Some coarse particles are present, a result of the powder being recycled. Material has been built in different directions relative to the build plane as defined in Figure 2 above. Evaluations are done in the 0°, 45° and 90° directions. For testing of selective laser melted material properties presented in the current paper testing has been conducted on as-manufactured material. Reference material in hot-rolled condition is typically not available in any other condition than the standard solution heat treated material state. Therefore, comparative data for standard Hastelloy X material is included as reference. For Alloy X material manufactured by the SLM method, the best heat treatment route is not per say a standard solution heat treatment. In fact, the material is in the as-manufactured state very homogeneous with no segregations opposite to what could be expected from, for instance, a casting process. I.e., from a segregation point of view, a solution heat treatment would not necessarily be beneficial. 2.3. Mechanical testing and evaluation Material testing has been performed at ambient and elevated temperature. At ambient temperature, the material has previously been shown to exhibit anisotropy in tensile properties [13, 14]. The current work tries to evaluate some of the high temperature properties of the selective laser melted Alloy X material with respect to thermomechanical fatigue (TMF) and creep loading. The resulting fracture surfaces and microstructures are evaluated by light optical and scanning electron microscopy. Etching of the material is done as electrolytic etching in 10% oxalic acid in distilled
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