70年代中期,美国麻省理工学院的科研人员首次展示出,能够在半固态温度成型软化的触变。触变材料以半固态物质存在,当在剪切作用下粘度减小时回复为更象液体的状态。研究人员发现,当合金冷却到液相线和固相线之间的温度时用力进行搅拌,正常形成的枝晶状固体破碎成大致球状的变质枝晶颗粒。由这些固体和残留液相形成的半固态悬浮液具有触变性能。当剪切停止并保持半固态温度时,合金悬浮液的粘度增加,能 In the mid-1970s, researchers at the Massachusetts Institute of Technology demonstrated for the first time the ability to soften thixotropy at semi-solid temperature. Thixotropic materials exist as semi-solid materials, returning to a more liquid-like state when the viscosity decreases under shear. The researchers found that when the alloy was cooled to a temperature between the liquidus and the solidus, agitation was forced on the normally dendritic solid to break into roughly spherical degenerated dendrites. Semi-solid suspensions formed from these solids and residual liquid have thixotropic properties. When the shear stops and maintains the semi-solid temperature, the viscosity of the alloy suspension increases