Page 54 - MSAM-1-2

Materials Science in Additive Manufacturing Process study of DED steel matrix composites

the accuracy of the prediction. The Taguchi method was
effective in determining the optimal set of parameters for
DED 316L/TiB MMC.
2
4. Conclusions
In this study, 316L/TiB MMC was successfully fabricated
2
using DED. The effect of DED process parameters on the
microstructure and mechanical properties of 316L/TiB
2
MMC was studied. The L9 Taguchi array was used to
vary laser power, scanning speed, and hopper speed at
three levels to optimize the mechanical properties of
316L/TiB .
2
It was found that the laser power, scanning speed,
Figure 8. Main effect graph for sample density. and hopper speed had negligible effects on the density
of the samples produced. Although 6 wt.% of TiB is
2
added, the average weight fraction of TiB in DED
2
316L/TiB was calculated to be 2 wt.%, indicating loss
2
of TIB during the DED process. Tumble mixing was
2
found to be unsuitable for the preparation of powder
mixture feedstock for DED as it does not result in
sufficient adhesion between the TiB and 316L stainless
2
steel particles. No pore and crack were observed in
all the DED samples. Columnar grains were found
predominantly within the layers while equiaxed grains
were found at the interlayer zones for the DED samples.
Fine and intricate sub-grains were also observed
within the grains. EDS analysis showed that the sub-
grain boundaries are enriched with molybdenum and
chromium. The microhardness of DED 316L/TiB MMC
Figure 9. Main effects graph for microhardness. 2
ranged between 168.5 HV and 186.4 HV.
Table 8. Response for microhardness In the future, effect of different powder preparation
methods for 316L/TiB can be studied to improve the
2
Level Laser power Scanning speed Hopper speed efficiency of the process. Then, the different compositions
1 45.21 45.06 44.97 of MMC can be investigated to expand the material library
2 45.10 44.97 44.92 available for the DED process.
3 44.89 45.16 45.31 Acknowledgments
Delta 0.32 0.19 0.39
Rank 2 3 1 The authors acknowledge the support from National
Additive Manufacturing Innovation Cluster (NAMIC),
Singapore, for the use of the AM facilities.
Hopper speed was found to be the most influential
in affecting the microhardness of the DED 316L/TiB Funding
2
MMC, followed by laser power and scanning speed.
The optimum parameters for maximum hardness were S. L. Sing would like to acknowledge the funding support
found to be laser power of 1000 W, scanning speed of from Singapore Ministry of Education Academic Research
600 mm/min, and hopper speed of 400 rpm. This gives a Fund Tier 1 (Award No.: 22-3721-A0001).
predicted microhardness of 182.5 HV. As these optimum Conflict of interest
parameters are identical to Taguchi No. 3, there is no
confirmation run conducted. The experimental value of The authors declared no potential conflict of interest with
microhardness obtained from this run is 186.0 HV which respect to the research, authorship, and/or publication of
means the predicted value has a 1.9 % error which showed this article.

Volume 1 Issue 2 (2022) 8 http://doi.org/10.18063/msam.v1i2.13