| 摘要 |
A method of preparing copper-bismuth alloy with a refined grain structure comprises casting an ingot of copper-bismuth alloy, containing 0.05-1% bismuth by weight, and thereafter extruding the alloy at 300 DEG -950 DEG C. Before extrusion, the ingot is machined to produce a billet which may be encased in a copper can, the ends of which are sealed with welded-in copper plugs. The can may be evacuated before being sealed. Extrusion may be through a die of circular or, for producing strip material, rectangular cross-section, after which the copper sheathing is removed by machining. Extrusion ratios of 4:1 and grain sizes of 0.1 mm. diameter and 0.2-0.3 mm. are referred to. In an example extruded at 500 DEG C., the alloy was then annealed at 800 DEG C. for one hour. |
