| 摘要 |
PURPOSE:To obtain a shape memory alloy having extremely uniform superfine- grained crystals, by refining a copper shape memory alloy in a vessel whose internal surface is composed of a calcia refractory material under specific conditions so as to elute specific amounts of Ca in a melt. CONSTITUTION:The copper shape memory alloy is refined in the vessel, whose internal surface is composed of calcia refractory material, by maintaining the molten alloy at a temp. higher than the melting point of the alloy by 100 deg.C or by holding the molten alloy under a reduced-pressure atmosphere, by which Ca is eluted from the internal surface of the vessel, so that copper shape memory alloy containing 50-500ppm Ca can be obtained. The eluted Ca satisfactorily acts on grain refining and, as a result, mechanical properties of the alloy can be improved.
|
