Page 68 - MSAM-3-3

Materials Science in Additive Manufacturing In-situ alloying of Ti41Nb by LPBF

A B

C D

E

Figure 12. Mean layer HV values versus volumetric energy density: (A) top layer, (B) layer 2, (C) layer 3, (D) layer 4, and (E) base layer of samples 60-1
to 60-4

Three tensile coupons for each parameter were tested, Table 5. Summary of tensile properties
and their average values are presented in Table 5.
Sample Elastic Yield stress Ultimate tensile Elongation to
Samples with a 10 mm hatch spacing were found to have modulus (0.2%) strength (MPa) failure (%)
higher yield strength and ultimate tensile strength (UTS) (GPa) (GPa)
than those with a 1 mm hatch spacing. This can be attributed 481-1 53±9 610±90 826±44 15.8±3.0
to the higher amount of dissolved Nb content at longer stripe 481-10 78±16 800±90 1007±38 13.7±0.9
lengths, leading to additional solid solution strengthening. 317-1 51±3 720±40 876±21 26.3±3.3
Conversely, an inverse trend was observed in ductility. Sample 317-10 58±4 810±10 1005±6 13.7±4.0
481-1 exhibited higher ductility than sample 481-10 due to
the lesser amount of porosity. Meanwhile, sample 317-1 was
significantly more ductile than sample 317-10, possibly due of porosities observed in the processing parameters, as
to the presence of a large amount of unmelted β-Ti stabilizer, shown in Figure 6, where porosity analysis also identified
which can enhance the ductility of the product. The low significant porosities located away from the core region of
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ductility of sample 317-10 may also be attributed to the the specimen. Hence, the actual tensile failure zone lies in
possible ω phase precipitation, which can reduce ductility the region where most porosities are found.
18
iso
while increasing the strength of the sample. 39,40
It is noteworthy that tensile specimens 481-10 had two 4. Conclusion
out of three tensile coupons that fractured outside the This study delves into the effects of thermal rest time
expected zone of failure (neck of the coupon), near the variation on in situ alloying of Ti41Nb (wt.%) within a
clamping point. This could be due to the large number single part. Key findings include:

Volume 3 Issue 3 (2024) 11 doi: 10.36922/msam.3506