Page 42 - MSAM-2-2

Materials Science in Additive Manufacturing Tensile and fatigue properties of Ti6Al4V SLM parts

A

B

C

D

Figure 9. (A) Example of surface analysis on specimen 8. (B) Striation marks with varying degrees of magnifications. (C) Distinct microstructure with
varying degrees of magnifications. (D) Defects and porosities with varying degrees of magnifications.

4.3. Fatigue property good log-stress versus log-cycles graph, there should be
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three results with cycles from 10 to 10 , 3 results from
4.3.1. Fatigue measurement
10 to 10 , and 1 fatigue limit that is above 10 mill cycles.
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Despite the changes, the number of cycles to failure is very Since we lacked data points in the range of 10 – 10 , in
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small and show extremely poor fatigue strength. Poor experiments 13 – 15, we tested specimens with % yield
fatigue life may be attributed to poor grinding and warpage strength in between 10% and 15%. However, all the
of the specimen, as shown in Figure 6. For the next batch of results resulted in cycles over fatigue limit. Possible cause
specimens, it was decided that they would be printed directly of the improvement in the fatigue cycle life may be the
on the plate so that the supports to be removed were only at improvement of the human factor of the grinding and
the arch. There should also be less warpage without supports polishing process on the later fabricated samples. Grinding
since there is more surface area on the substrate plate for the on the surface in specimen 8 and thereafter showed visible
heat to dissipate, resulting in lesser internal stresses. improvements in surface quality. For experiments 16 and
From experiments 8 to 12, the number of cycles 17, we tested high % yield strength on the specimens that
increases as the % yield strength decreases. To plot a had already reached >10 mill cycles. This was to see if the

Volume 2 Issue 2 (2023) 9 https://doi.org/10.36922/msam.0912