INFLUENCE OF ADDITION OF Fe, Co or Ni ON THE PROPERTIES OF AN ANTIFERROMAGNETIC INVAR-TYPE ALLOY ″VOLCOLOY″ IN THE Mn-Ge SYSTEM.

The thermal expansion, magnetic properties, lattice constants, hardness and workability were measured for Mn-Ge based ternary alloys cooled at various rates after homogenizing at 1100 K for 10. 8 ks. In the thermal expansion curves of Mn-20 and 22%Ge alloys containing Co or Ni less than 5% and 10%Fe, the Neel temperature of the epsilon -phase appeared. The zero region of the thermal expansion coefficient at room temperature is widened by Fe addition and is narrowed by Ni or Co addition. The Vickers hardness of Mn-20%Ge-Fe alloys is lowered by Fe addition, keeping a constant value of 400 up to 10%Fe. The machinability and forgeability are better than the binary alloys.