Effects of Ti on the solidification and crystallization behavior of nanocomposite permanent material under different cooling rates

Abstract

Effects of Ti on the crystallization behavior, phase composition, microstructure and magnetic properties of Nd2Fe14B/α-Fe dual-phase nanocomposite permanent magnet materials in different states were studied, respectively. The results show that Ti could affect the solidification and crystallization behavior of dual-phase nanocomposite materials by regulating the cooling rate during the rapid solidification process. When the cooling rate is slow, part of Ti atoms enters the soft magnetic phase α-Fe, and part forms the TiFe2 phase around the hard magnetic phase. Exchange coupling is enhanced. The maximum energy product and the remanence of the alloy are 10.54 MGOe and 8.34 kGs, respectively. When the cooling rate faster, Ti can stabilize another ferromagnetic ThMn12-type phase with a low coercivity and maximum energy product, which should be avoided. When the cooling rate is fast enough to form amorphous, Ti and Fe preferentially combine to form the TiFe2 phase during crystallization, which selectively inhibits the growth of the hard magnetic phase and the precipitation of the soft magnetic phase, resulting in a significant enhancement of coercivity to 12.82 kOe. By regulating the mechanism of Ti in the solidification and crystallization process, nanocomposite permanent magnet materials with varying magnetic characteristics can be obtained, offering a flexible approach to tailoring their performance according to specific application requirements.