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Materials Science in Additive Manufacturing In situ electromagnetic field manipulation during LMD

cooling rate is affected by the effect of multiple remelting, EM-3 with increasing electromagnetic field strength. The
which leads to the formation of columnar grain. constant electromagnetic field inhibits the molten pool
flow and subsequently shifts its direction (Figure 6). When
3.4. Texture analysis the flow velocity of the disordered molten pool dominates,

ImageJ was used for statistical analysis of the length the growth of grains is interrupted, and the grains are
distribution of β-columnar grain size (Figure 3), and refined (Figure 9B). The flow velocity slows down, and
the results are presented in Figure 9. The average length the cooling rate decreases when the inhibition of molten
of β-grains in sample EM-0 is 490 μm (Figure 9A). The pool flow is dominant, promoting the growth of grains
length of β-columnar grains significantly decreases from (Figure 9C and D). The phase map (Figure 10) displays
490 μm to 354 μm in an electromagnetic field strength of the contents of α-Ti in samples EM-1, EM-2, and EM-3,
39.40 mT. The average length of β-grains in samples EM-1, which changed from the initial 98.1% to 98.3%, 97.9%,
EM-2, and EM-3 is 354, 446, and 426 μm, respectively, and 96.8%, respectively. The phase content revealed no
under the electromagnetic field (Figure 9B-D). From obvious variations, which suggests that the introduction
the histogram, the frequency of short β-columnar grains of a magnetic field to the LMD process does not induce a
(<200 μm) increased to 15.5%, suggesting that the constant drastic phase transition.
electromagnetic field positively influences the grain size of Figure 11 displays the pole figures of the α-phase
the Ti-6Al-4V alloy in LMD. The elongated large-sized
β-columnar grains can be observed in samples EM-2 and in the Ti-6Al-4V alloy deposition layer under different

A

B

C

D

Figure 11. Pole figures of the α-phase in the plane (0001), (11 – 20), and (10 – 10) of Ti-6Al-4V alloy deposition layer: (A) EM-0; (B) EM-1; (C) EM-2;
and (D) EM-3

Volume 4 Issue 1 (2025) 13 doi: 10.36922/msam.8332