1984 年 25 巻 11 号 p. 828-835
Magnetic properties, the thermal expansion, the lattice constants, the hardness and the workability were measured for Mn-22%Ge based ε phase ternary alloys containing transition metals in groups IVA, VA and VIA of the periodic table, when they were cooled at various rates after homogenizing at 1100 K for 10.8 ks.
The magnetizations of the Mn-22%Ge based ternary alloys show a temperature variation similar to that of the Mn-22%Ge binary alloy and an abrupt decrease near the Néel point TN. The ternary alloys also indicate a minimum in the electrical resistivity at TN. The Néel point of the ε phase moves toward the lower temperature side with an increase in the concentration of the third element. The transformation from ε to ε1 does not occur readily by addition of a few percent of the third elements, keeping the nature of the binary alloy system.
In the thermal expansion curves of the Mn-22%Ge based ternary alloys there appears a minimum corresponding to the Néel point of the ε phase, showing the Invar characteristics. The thermal expansion coefficient of the ternary alloys in the vicinity of room temperature decreases at first with the addition of the third element, and then appears to increase to a positive value after passing through zero or a small negative minimum value. The spontaneous volume magnetostriction of a Mn-22%Ge-4%Cr alloy at 77 K is 1.3×10−2, and the value is less affected by the addition of a few percent of Cr. The Vickers hardness of the ternary alloys shows a smaller value than that of the Mn-Ge binary alloys.
