The master alloy
used for rapid solidification is prepared from
raw materials of iron, silicon, and copper chunks (>99.9%). Alloy
raw materials with different Cu contents (0–2.5 wt %) were
repeatedly smelted (6–8 times) in a high-vacuum arc melting
furnace to prepare alloy ingots. After that, the master alloy was
remelted in a quartz crucible of a high-vacuum single-roll belt spinning
furnace using a high-efficiency electromagnetic heating device. Before
preparing the steel strip by rapid solidification, the vacuum degree
of the melting chamber of the strip furnace was controlled below 6.0
× 10–4 Pa, and then Ar (99.99%) was injected
to make the vacuum degree of the melting chamber −0.07 to −0.04
MPa. The molten Fe–Si master alloys with different Cu dosages
were injected onto a rotating copper roll using high-purity Ar and
spun into a strip (Figure 1 ). The wheel speed of the copper wheel was precisely controlled
and monitored by motor control system. A thermal camera was set up
to record the ribbon surface temperature through a sapphire window
during the melt spinning process. Multiple frames were used to acquire
the average cooling rate for wheel speed. The spouted molten master
alloy forms a high-silicon steel strip with a cooling rate of 8 ×
105 K/s (30 m/s).
The thermal evolution of the Fe–Si–Cu
steel strip
samples was conducted using thermogravimetric analysis and differential
scanning calorimetry (TG-DSC, Mettler TGA/DSC3+) equipment from room
temperature to 1000 °C with a heating rate of 5 °C/min.
The grain morphology and the texture of Fe–Si–Cu steel
strip sample were characterized by electron back-scattered diffraction
(EBSD, Oxford SYMMETRY), and data analysis was postprocessed with
HKL-Channel 5 software to characterize. Considering typical orientations
that are developed in silicon steel (Figure 2 ), φ2 = 0° and φ2 = 45° orientation distribution function (ODF) sections
were used in this study. The hysteresis loops of the steel strip samples
were confirmed by vibrating sample magnetometer (VSM, MPMS-VSM, and
MPMS-XL) devices at 25 °C. Vickers hardness and engineering stress–strain
curves of the samples were obtained with HVS-30 and Instron-3344 devices.
Modeling by density functional theory (DFT) and
simulation calculations
for phase stability and magnetic properties. The compositions are
assumed to be Fe-12 atom % Si (equivalent to 6.4 wt % Si) and Fe-12
atom % Si-1 atom % Cu (equivalent to 6.4 wt % Si, 1.3 wt % Cu). The
exchange-correlation energy was calculated using the generalized gradient
approximation and the projector augmented wave method in the Vienna
Ab-Initio Simulation Package, and the plane wave energy cutoff was
350 eV. A 2 × 2 × 2 supercell of 16 atoms was used for the
modeling with the lattice parameters of a = b = c = 5.7328 Å of the bcc lattice.
Fe–Si alloys (VCA = 0.88, 0.12) and Fe–Si–Cu
alloys (VCA = 0.87, 0.12, 0.01) were simulated by virtual crystal
approximation. A Γ-centered grid of 4 × 4 × 4 k-points was used for Brillouin zone sampling, and a tetrahedron
method with Bloch corrections was used for the k-point
integration.
used for rapid solidification is prepared from
raw materials of iron, silicon, and copper chunks (>99.9%). Alloy
raw materials with different Cu contents (0–2.5 wt %) were
repeatedly smelted (6–8 times) in a high-vacuum arc melting
furnace to prepare alloy ingots. After that, the master alloy was
remelted in a quartz crucible of a high-vacuum single-roll belt spinning
furnace using a high-efficiency electromagnetic heating device. Before
preparing the steel strip by rapid solidification, the vacuum degree
of the melting chamber of the strip furnace was controlled below 6.0
× 10–4 Pa, and then Ar (99.99%) was injected
to make the vacuum degree of the melting chamber −0.07 to −0.04
MPa. The molten Fe–Si master alloys with different Cu dosages
were injected onto a rotating copper roll using high-purity Ar and
spun into a strip (
and monitored by motor control system. A thermal camera was set up
to record the ribbon surface temperature through a sapphire window
during the melt spinning process. Multiple frames were used to acquire
the average cooling rate for wheel speed. The spouted molten master
alloy forms a high-silicon steel strip with a cooling rate of 8 ×
105 K/s (30 m/s).
The thermal evolution of the Fe–Si–Cu
steel strip
samples was conducted using thermogravimetric analysis and differential
scanning calorimetry (TG-DSC, Mettler TGA/DSC3+) equipment from room
temperature to 1000 °C with a heating rate of 5 °C/min.
The grain morphology and the texture of Fe–Si–Cu steel
strip sample were characterized by electron back-scattered diffraction
(EBSD, Oxford SYMMETRY), and data analysis was postprocessed with
HKL-Channel 5 software to characterize. Considering typical orientations
that are developed in silicon steel (
were used in this study. The hysteresis loops of the steel strip samples
were confirmed by vibrating sample magnetometer (VSM, MPMS-VSM, and
MPMS-XL) devices at 25 °C. Vickers hardness and engineering stress–strain
curves of the samples were obtained with HVS-30 and Instron-3344 devices.
Modeling by density functional theory (DFT) and
simulation calculations
for phase stability and magnetic properties. The compositions are
assumed to be Fe-12 atom % Si (equivalent to 6.4 wt % Si) and Fe-12
atom % Si-1 atom % Cu (equivalent to 6.4 wt % Si, 1.3 wt % Cu). The
exchange-correlation energy was calculated using the generalized gradient
approximation and the projector augmented wave method in the Vienna
Ab-Initio Simulation Package, and the plane wave energy cutoff was
350 eV. A 2 × 2 × 2 supercell of 16 atoms was used for the
modeling with the lattice parameters of a = b = c = 5.7328 Å of the bcc lattice.
Fe–Si alloys (VCA = 0.88, 0.12) and Fe–Si–Cu
alloys (VCA = 0.87, 0.12, 0.01) were simulated by virtual crystal
approximation. A Γ-centered grid of 4 × 4 × 4 k-points was used for Brillouin zone sampling, and a tetrahedron
method with Bloch corrections was used for the k-point
integration.
