Invar® Discovery

Invar® is a 36 % iron nickel (FeNi36) alloy which has a coefficient of thermal expansion of virtually zero at temperatures ranging from cryogenic to ambient.This specific property giving birth to Invar® in 1896 has been discovered by Charles-Edouard Guillaume, Swiss physician Nobel Prize in 1920, together with Imphy. Since the early 1890s, the Imphy works has been working on nickel alloys. The works consequently became the ideal associate of Charles-Edouard Guillaume's experiments.After Invar® discovery, many searchers - among which Pierre Chevenard - explored nickel alloys' properties throughout the 20th century. Invar® gave then birth to many other alloys with physical and mechanical properties.More than ever, Invar®is a key alloy in many applications requiring of course a very low CTE but also good workability and weldability : LNG tanks, cryogenic fluid transport and transfer pipes, electronic packages, frames of deep-space telescopes, echoboxes for telephone ground relay stations, heat sinks, machine tool parts...Invar® has been a trade mark of Imphy Alloys since 1907. Imphy research engineers and engineers' knowledge about Invar® and other iron nickel alloys have been published in a book, the Iron Nickel Alloys, edited by Tec & Doc Lavoisier.