【摘要】 鉴于超塑性和蠕变变形中存在大量位错的实验事实,将晶粒内部平均位错数量引入到Ruano-Wadsworth-Sherby归一化的晶粒尺寸—应力的变形机理图中,以双相Mg-8.42Li合金为例获得了包含位错数的归一化晶粒尺寸和应力的新型变形机理图.归一化晶粒、应力实验数据和计算的位错数与变形机理图对照,表明双相镁锂合金在423~623K低应变速率下主要的变形机理为晶格扩散控制的晶界滑移.含位错的变形机理图建立了塑性应力、晶粒尺寸及位错数量之间的定量联系,预报了该合金在423~623 K条件下的位错特征.更多还原

【Abstract】 In view of vast experimental evidence of dislocation activities in superplasticity and creep,average dislocation quantities inside grains were incorporated into the Ruano-Wadsworth-Sherby(R-W-S) deformation mechanism map(DMP) with normalized grain size and stress,and new DMPs with normalized grain size,stress and dislocation quantity were established for two-phase Mg-8.42Li alloy as an example.It is concluded that the dominate deformation mechanism for duplex magnesium lithium alloy in the temperature range of 423 K to 623 K and at lower strain rates is grain boundary sliding controlled by lattice diffusion through the comparison of normalized experimental stress,grain size and calculated dislocation quantity with constructed DMPs.The DMPs incorporating dislocations ascertained the quantitive relationship among plastic stress,grain size and dislocation quantity and predicted the dislocation feature of the alloy in the temperatures range of 423 K to 623 K.更多还原