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本文研究了超硬铝LC~9在超塑变形过程中变形机理的转化。热变形激活能Q值随应变量的增加而下降,应变速率敏感性指数m值随应变量的增加而上升,表明了变形机理由晶内滑移转变为晶界滑移为主。显微观察表明:)动态再结晶造成晶粒的微细化;)晶内位错密度相对减少,晶界附近位错密度相对增加,发生了以动态再结晶为主的软化过程,但该过程受到弥散分布的强化相质点的抑制,引起显微组织的等轴微细化,从而导致以晶界滑移为主的变形过程,即动态再结晶诱发微细晶粒超塑性。
In this paper, the deformation mechanism of superhard aluminum LC ~ 9 during superplastic deformation was studied. The Q value of the thermal deformation activation energy decreases with the increase of the strain amount, and the value of the strain rate sensitivity index m increases with the increase of the strain amount, indicating that the deformation mechanism changes from intragranular slip to grain slip. Microscopic observation shows that: dynamic recrystallization causes grain refinement;) the dislocation density in the grain is relatively reduced, and the dislocation density in the grain boundary is relatively increased, and the dynamic recrystallization-based softening process occurs, but the process is affected Dispersion of the strengthening of the phase particles inhibited, causing the microstructure of the equiaxed micronization, resulting in the grain boundary-based deformation process, that is, dynamic recrystallization induced fine grain superplasticity.