Effect of order-disorder transition on magnetic properties of rapidly soldified high silicon-iron ribbons
The effect of ordering on the soft magnetic properties of 6.5% silicon-iron ribbons obtained by rapid solidification is studied. The atomic order cannot be prevented by the fast cooling. It is shown that isothermal aging at 700 degrees C induces a small decrease in coercive force and hysteresis losses, while aging at 500 degrees C induces an increase in these parameters. The magnetic evolutions are corroborated by Lorentz microscopy observations. The values obtained and the observations suggest a weak individual interaction, which may be due to local variation of exchange and anisotropy energy. >
Role of material purity on the structural and magnetic properties of rapidly solidified FeSi 6.5 wt% alloys
Abstract A study has been made on the structural and magnetic properties of rapidly quenched FeSi 6.5 wt% alloys, obtained from high purity (HP) and commercial purity (CP) master alloys and characterised upon a range of annealing treatments. Superior magnetic behavior is exhibited by the HP alloys after annealing, which correlates with enhanced growth of a favourable cube-on-face crystallographic texture. As suggested by metallographic analysis, a surface energy mechanism appears to control the evolution of such texture, with a critical role being played by solute oxygen. Mechanical strength and ductility also appear improved in the HP samples. Substantial loss of Si and weakening of the texture are however observed after high temperature annealing ( T > 1200°C), with ensuing deterioration of the material soft magnetic properties. It is concluded that optimum dc and high frequency magnetic behavior of HP and CP alloy ribbons requires annealing treatments at temperatures around 1100–1150°C, where the achieved material structure provides minimum losses and maximum permeability and the high Si concentration of the as-quenched material is retained.
Finite Difference Modeling on the Temperature Field of Substrate in Friction Surfacing
Friction surfacing is an advanced process of great potential, especially in the field of repair and reclamation of worn and damaged components. As a kind of thermal processing technology, the temperature profile and changes of the substrate in friction surfacing are important factors to get coatings of high quality. In this paper, the temperature field of the substrate during the process is simulated by finite difference method. The results are consistent with experiments, reappearing the temperature change of the substrate during friction surfacing, allowing further study on figuration and quality of coatings.