Every freely fetchable raw source consulted 2026-09-10 (Wikipedia Beryllium copper, Wikipedia Beryllium, beryllium.eu Facts and Figures) places the alloy only in the 1920s decade, with no source giving a single confirmed exact year; Britannica, ScienceDirect and Thomasnet refused automated fetch and briandcolwell.com failed on a TLS handshake before any content loaded.
What would resolve this A metallurgical history source (a patent record naming the original filer and filing year, or a peer-reviewed materials-science history article) that names the specific year copper-beryllium age-hardening was first patented or first used commercially, distinct from the unrelated 1928 Corson-bronze (copper-nickel-silicon) patent.
OpenHistory of MetallurgyBeryllium Copper (Wikipedia)