Mines Branch Information Circular IC 235 SUPERPLASTICITY

摘要

The superplasticity phenomenon, which is characterized by a metal's capacity for a large degree of relative uniform extension, is reviewed for the purpose of assessing both its potential applicability to practical metallurgical operations and the possible benefits to be derived from further research and development. Detailed are the re-quirements for a metal to be superplastic, as well as the conditions necessary for the phenomenon to occur. Twenty-nine metal systems reported to be superplastic are listed, including pure metals and single-phase and multi-phase alloys. A number of the methods are reviewed that are employed to generate the required fine grain structure—in the order of a micron--mechanically by extrusion or rolling, or thermally by eutectoid decomposition or compact sintering.