Development of Solid Solution Strengthened High Purity Beryllium Alloy Sheet

摘要

Three beryllium plus copper alloy ingots were produced. The charges were melted under a vacuum of approximately 150 microns in a BeO coated graphite crucible. At 2460 F the alloy was bottom poured into a 3-1/4 in. diameter graphite mold having a water cooled chill plug attached at the bottom. Preparatory to melting, beryllium electrolytic flacke was cold compacted into cylindrical preforms to minimize melt loss. The copper was added in sections cut from electrolytic copper cathodes. The billets were encased in mild steel jackets and extruded. The extrusion was performed at 1850 F using a 1/4 in. x 1-1/2 in. die which produced a 14.3:1 reduction ratio. Conclusions are: (1) Copper additions to high purity beryllium yield an alloy with good casting characteristics. (2) Only the increased extrusion forces required to extrude the alloy billets differentiated the alloy extrusions from conventional beryllium ingot extrusions. (3) The degree of surface roughness of the extruded alloy slabs was greater than the roughness of pure beryllium slabs, and this roughness could be related to the grain size variation in the casting. (Author)