虽然人们认识金属的超塑性现象已经五十余年了。但只是最近十年超塑性金属才在工业上得到应用。超塑性金属的流动应力对应变速率很敏感(即敏感系数“m”值很高)。在慢应变速率下变形,超塑性合金则具有很高的拉伸性能(延伸率常常大于1000％)。金属产生超塑性的前提是它们具有微细晶粒尺寸,晶粒具有这样的尺寸,就能在高温下维持稳定。现在研究出晶粒细化和晶粒尺寸控制的两种方 Although people know the phenomenon of superplasticity of metal for more than fifty years. But only superplastic metals have been used in industry in the last decade. The superplastic metal flow stress is very sensitive to the strain rate (ie, the sensitivity coefficient “m” value is high). When deformed at a slow strain rate, superplastic alloys have very high tensile properties (elongation often greater than 1000%). Metals produce superplasticity on the premise that they have a fine grain size, the grain has such a size, will be able to maintain stability at high temperatures. Now studied the grain refinement and grain size control of the two parties