Introduction
Magnetic alloys composed of aluminum, nickel and zinc have been widely used in many industries due to their excellent magnetic properties and good electrical conductivity. AlNiZn alloys are attractive due to their high coercive forces, low coercivity, good resistance to oxidation and corrosion, and good thermal stability. The addition of titanium to the AlNiZn alloy system can produce a variety of different magnetic phases depending on the alloy composition, microstructure and fabrication technique. The current research on AlNiZn alloys focuses on developing magnetic alloys with improved properties and optimizing the alloy microstructure. In this paper, the effects of the addition of titanium to AlNiZn alloys on the magnetic properties and microstructure are evaluated.
Experimental
AlNiZn-Ti alloys were prepared from commercially available elements. Powdery Al (99.5% pure), Ni (99.5% pure) and Zn (99.99% pure) with 6.0 and 0.5 wt.% of Ti were used. The mixtures were placed in aluminum crucibles and induction heated at 1000 °C for 1 hour before being poured into graphite molds. The ingots were homogenized at 1100 °C and forged into bars. The bars were annealed at 850 °C for 2 hours and then cooled to room temperature.
Analysis
The sectioned alloys were characterized using x-ray diffraction to determine the phase composition. Differential scanning calorimetry (DSC) was used to identify the phase transitions and form a cooling curve. The surface of the alloy samples was studied using scanning electron microscopy (SEM) to observe the microstructure. To measure the magnetization, the sample was placed in a superconducting quantum interference device (SQUID) magnetometer. The magnetic properties of the AlNiZn-Ti alloys were measured by subjecting them to a magnetic field of -100 kOe and +100 kOe.
Results and Discussion
The x-ray diffraction spectra show that aluminum and nickel are the main phases present in the AlNiZn-Ti alloys. The addition of titanium to the alloy system has caused minor changes in the lattice parameters and improved the crystalline nature of the matrix. The DSC analysis demonstrates that the addition of titanium to the AlNiZn alloy system produces two endothermic peaks at 743 °C and 881 °C, corresponding to the crystallization of the two solid solution phases.
SEM analysis reveals that the addition of titanium to the AlNiZn alloy system has led to the formation of a columnar structure with a stronger grain boundary compared to the single-phase alloys. The magnetic properties of the AlNiZn-Ti alloys were measured using SQUID magnetometry. The results show that the coercivity of the alloys increases with the addition of titanium, indicating an improved magnetic property. The saturation magnetization values decrease slightly with the addition of titanium due to the presence of titanium in the secondary phases.
Conclusion
AlNiZn-Ti alloys produced using high-temperature powder metallurgy show promising magnetic properties. The addition of titanium to the AlNiZn alloy system has caused minor changes in the lattice parameters and improved the crystalline nature of the matrix. The coercivity of the alloys increases with the addition of titanium, indicating improved magnetic properties. The magnetic properties of the AlNiZn-Ti alloys were also examined using x-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and superconducting quantum interference device magnetometry. The results show that the addition of titanium has improved the magnetic properties of the AlNiZn alloys significantly.
