Effect of Low-Temperature Treatment on the Structure and Physical Properties of Castable Carbon-Containing Invar Alloys

摘要

The effect of low-temperature thermocycling treatment of castable invar alloys on the microstructure and temperature coefficient of linear expansion (CLTE) is studied. The tooling used in the production of precision articles from carbon-filled plastic should possess a maximum CLTE, temperature stability of the structure, and invariability of the coefficient of thermal expansion under the impact of thermal cycles. It is shown that an optimum castable invar alloy with steadily low coefficient of thermal expansion should contain at least 32.7 wt.% nickel and about 0.8 wt.% additional carbon. The effect of the distribution of carbon in the alloy on its structural stability is discussed.