In this paper, the structure characteristics and magnetic properties of Fe₈₃Si₆B₆P_1.5C_1.5Cu₁Nb₁ amorphous alloy ribbons annealed at 550 °C for different times were systematically investigated using X-ray diffraction, vibrating sample magnetometer, and atom probe chromatography. The results show that high-density Cu atomic clusters of appropriate sizes help to stabilize the α-Fe(Si) phase and improve the uniformity of the grains to enhance the soft magnetic properties. The solubility difference between the α-Fe(Si) phase and the B-rich phase, the formation of a localized amorphous structure in the transition region, and the inhibition of nanograin growth. However, when the annealing time is extended, the size of the α-Fe(Si) grains decreases, the grain boundary density increases and secondary phases such as Cu clusters become pinning sites for magnetic domain walls. This leads to a decrease in soft magnetic properties, an increase in hard magnetic properties, and a rapid increase in coercivity. When annealed at 550 °C for 20 min, the number density of Cu atomic clusters was 9.18 × 10²² m⁻³, the spherical equivalent radius was 1.13 ± 0.29 nm, and the ribbons had good soft magnetic properties with a coercivity of 4.59 Oe. The saturation magnetic induction reached a peak value of 185.11 emu/g.

In this paper, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray stress meter (XRSA), atom probe tomography (APT), hardness, and tensile tests were used to study the effect of tempering temperature on the microstructure and properties of Fe-9Ni-2Cu steel. The results show that after the quenched samples were tempered at 460 °C for 2 h, the hardness values increased from 373 to 397 HV, and elongation also increased from 13% to 16%. With the tempering temperature increasing from 460 to 660 °C, the hardness firstly decreases from 397 to 353 HV and then increases to 377 HV, while the elongation increases to 17% and then decreases to 11%. The variation of the mechanical properties greatly depends on the evolution of the Cu-rich phase and carbides. The precipitation strengthening of the Cu-rich phase and carbides leads to the increase of hardness, but when the precipitate is coarsened, the precipitation strengthening weakens, and then, the hardness increases. When the tempering temperature is 560 °C, a large amount of stable reverse transformation austenite was formed with a content of 7.1%, while the tensile strength reached the lowest value of 1022 MPa and the elongation reached the maximum value of 17%.

Researchers are increasingly interested in the use of electromagnetic wave (EMW) absorbing materials in military and civic applications. In the subject of wave absorption, Ti3C2Tx-based composites have present promising application with satisfactory properties. In this study, microwave-assisted annealing of Ti3C2Tx@Co-MOF and Fe-MOF (Ti3C2Tx@CFMF) precursors at 450°C was applied to assemble Ti3C2Tx@CoFe@TiO2 nanocomposites. The in-situ formation of nanoparticles CoFe and TiO2 in the Ti3C2Tx interlayers to improve impedance matching and creates rich interface, enhanced interface polarization. The synergistic impact of various polarizations between Ti3C2Tx, TiO2 nanoparticles and CoFe nanoparticles, along with CoFe natural magnetic loss, results in efficient EMW absorption. The minimum reflection loss (RL) value for nanocomposites was -62.9 dB at 17.95 GHz with a thin thickness of 1.2 mm, while the effective absorption bandwidth (EAB) value was 5.02 GHz (12.74 GHz-17.76GHz) with a thickness of 1.4 mm. Decreased EMW absorbing performance after the annealing temperature is increased to 550°C. Due to CoFe and TiO2 nanograin size increases, which weakened interface polarization effect decreases, and Ti3C2Tx disappear. As a result of this study, a lightweight and high-performance EMW absorbent material has been obtained, which is promising for a variety of high-frequency EMW absorption applications.