Elinvar

Elinvar is a nickel steel alloy with a modulus of elasticity which does not change much with temperature changes. The name is a contraction of the French elasticité invariable (elastically invariable). It was invented in the late 1890s by Charles Édouard Guillaume, a Swiss physicist who also invented Invar, another alloy of nickel and iron, which has very low thermal expansion. Guillaume won the 1920 Nobel Prize in Physics for these discoveries, which indicates how important these alloys were for scientific instruments.