Abstract
Practical Invar alloys are all ferromagnetic, and applications of these alloys are often restricted because of their ferromagnetism. Therefore, research to develop magnetically insensitive Invar alloys has recently received considerable attention. In the present study, physical properties of Cr-base alloys containing small amounts of 5d transition metals have been investigated.
The Néel temperature of Cr increases with Re, Os, Ir, or Pt content and decreases with Ta or W content.
Some Cr-Fe primary solid solution alloys show very low thermal expansion coefficients below the Néel temperature, and the temperature range below room temperature, however, makes the alloys impractical. Therefore, we added 5d transition metals to the Cr-Fe alloys to increase the Néel temperature and found the Invar characteristic around room temperature in some of the Cr-Fe base ternary alloys. These Invar alloys are all antiferromagnetic and the magnetic susceptibilities are very small, showing that the Cr-Fe base ternary Invar alloys containing 5d transition metals are magnetically insensitive in practical applications.
