13th International Conference on Fracture June 16–21, 2013, Beijing, China -5- water with a voltage of 6V and a time of 15-25s depending on specimen size. In the current paper, material properties are only evaluated for bulk material, i.e. all material was machined to final specimen dimensions and no influence from the rough surface is taken into consideration. The thermomechanical data referenced below have been conducted as in-phase (IP) TMF between 50°C and 800°C and a hold time of 5 minutes at maximum temperature. Creep testing is performed at 816°C. 3. Results 3.1 Initial microstructure The typical as-manufactured microstructure is shown below, Figure 4. The microstructural anisotropy is obvious. As seen in Figure 4, the material has a weld-like structure. Due to the conditions during manufacturing, the material will undergo rapid solidification. In the literature, in the melt pool solidification region, temperature gradients up to 3500 K/mm on the surface are indicated [15]. The resulting grain size will be fine-grained as seen in Figure 5. 20µm 100µm 100µm 50µm a) b) c) d) Figure 4. As manufactured microstructure. Top views (a, b) are light optical micrographs, bottom views (c, d) are corresponding scanning electron microscope images. Left views (a, c): Arrow indicates the build direction. The build plane is horizontal and below the bottom of the figure. Right views (b, d): The build direction is out of the plane, the build plane is in the plane of the figure. From Figure 4 the micrographs a columnar structure can be observed. The grain structure is not
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