1984 年 25 巻 5 号 p. 348-355
The brittleness of Sendust with the nominal composition of 9.6 mass% silicon, 5.4 mass% aluminum and the balance of iron has been studied experimentally. By high thermal stress due to temperature gradient in the crystal, cleavage cracks along {001} plane or grain boundary cracks are easily introduced during either solidification after casting or subsequent heat treatments. The {001} cleavage cracks are also formed under applied external stress. Fracture stress of hot rolled Sendust examined by bending tests is higher than that of cast one, indicating the removal of internal defects by hot rolling. The single crystal which was prepared by zone-melting, and therefore, less-stressed thermally can be bent plastically even at room temperature, showing a lack of internal defects acting as the origin of cracking.
