Evaluation of manganese-copper-nickel alloys for use in thermobimetal

The paper discusses the various requirements of high expansion alloys used in thermobimetal, with a short review of commonly used alloys. Thermal expansion at different temperature ranges (from 30°C to 400°C), hardening due to cold rolling and recrystallization characteristics of five Mn-Cu-Ni alloys were studied with a view to evaluating their use in thermobimetal. It was found that Mn-Cu-Ni alloy with 75% Mn, 15% Ni and 10% copper gives comparably higher range of lenearity of the coefficient of expansion in the series and its mechanical properties and thermal stability makes it highly suitable for high sensivity thermobimetals. (Shri J. Bhattacharya, Scientist and Shri B.N. Das, Scientist and Head, Mechanical Metallurgy & Testing Division; National Metallurgical Laboratory, Jamshedpur)