A study on the microstructure of Alnico8 alloy thermomagnetically treated at various temperatures

The microstructure evolution of the Alnico8 alloy thermomagnetically treated at the temperatures of 800, 850, 865 °C was investigated by transmission electron microscope. The microstructure in both as-homogenized and thermomagnetically treated specimens consists of the rod-like Fe–Co rich phase and Ni–Al rich phase. During thermomagnetical treatment, the Fe–Co rich phase was coarsened to a certain size firstly, then split into smaller ones, which resulted in a more homogenous and finer microstructure. The result also indicates that the temperature of thermomagnetical treatment has great effect on the splitting process of Fe–Co rich phase. Based on the point of view of energy, the splitting process of Fe–Co rich phase was analyzed.