13th International Conference on Fracture June 16–21, 2013, Beijing, China -9- 3.3 Creep testing Results from stress rupture testing of SLM material is presented below, Figure 12. In the figure, the relative creep rupture life “1” indicates the normalized life for a hot-rolled material to yield a certain creep life. Corresponding fracture surfaces and crack patterns are shown in Figure 13. 0 0,2 0,4 0,6 0,8 1 1,2 SLM 0° SLM 45° SLM 90° hot-rolled bar specimen material variant normalized creep rupture life [-] Figure 12. Stress rupture testing at 815°C. Comparison of SLM material and hot-rolled Hastelloy X. B C Figure 13. Fracture surface, test temperature 815°C, build direction 0°, creep testing. Fracture is intercrystalline with multiple crack sites. Area “C” is an area with poor bonding (internal flaw) to the surrounding. 4. Discussion The tensile strength anisotropy has previously been indicated for Hastelloy X [13, 14, 16] and other alloys [11, 12, 17]. Here the anisotropy is obvious both in creep testing and in fatigue. The trend is that the 90 degree direction acts as the most fatigue and creep resistant direction. In this direction
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