MARTENSITIC TRANSFORMATION AND METALLURGICAL STUDY OF LOW TEMPERATURE Cu-Al-Be TERNARY ALLOY

Abstract
The present study on a Cu-Al-Be alloy has given the following characteristics : the addition of small concentration of beryllium to the eutectoïdal alloy close to Cu₃Al leads to a sharp decrease of the martensitic transformation temperatures. At the same time the composition corresponding to the maximum stability of the beta phase does not change significantly. The eutectoïdal temperature is lowered, but the temperature of beta solution treatment remains the same. Moreover there is no change in the nature of the martensitic transformation (DO₃ ↔ 18R). All these properties are very interesting from the industrial point of view : whatever is the M_s temperature chosen, the beta phase stability will be approximately the same since the alloy is always close to the "eutectoïdal" composition. This alloy will be the complement of Cu-Al-Ni alloy towards low transformation temperatures (from -200 °C to +60 °C) with approximately the same stability at high temperature.