作　　者： ; ; ; ;

机构地区： 江苏理工学院

出　　处： 《稀有金属材料与工程》 2019年第9期2864-2872,共9页

摘　　要： 为了探索晶界扩散作用下的相变过程,将晶界扩散耦合到定量的扩散控制相场模型,研究了Ti-6Al-4V合金多晶体系中的晶界数量、α相的空间分布和尺寸分布等对α相溶解的影响。结果表明:晶界是溶质扩散的快速通道,晶界边数越多,α相溶解速度越快,即当α相位于三岔点时,α相溶解最快。而α相位于晶界上和α相均匀分布基体中时,两种情况下的α相溶解速度差别较小。与二维条件下α相溶解速度相比,三维条件下的晶界扩散对α相溶解的影响更加显著;当相变以溶质的体扩散为主时,α相的空间分布是影响α相溶解的主要因素之一;但当相变以溶质的晶界扩散为主时,除了均匀尺寸分布外,其它尺寸分布对α相溶解影响不显著。 In order to study the phase transformations in consideration of the grain boundary diffusion,the diffusion along grain boundary was incorporated in the quantitative phase field model coupled with the Kim-Kim-Suzuki(KKS).The effect of the number of grain boundaries,the spatial distribution and size distribution(PSD)ofαphase on theαphase dissolution was researched.The results show that grain boundaries are a faster element diffusive path.The larger the number of grain boundaries is,the faster the kinetics ofαphase dissolution is.Namely,the kinetics ofαphase dissolution is fastest when the phase is located at triple junctions.However,the dissolution kinetics is of little difference whenαphase is on the grain boundary and distributed uniformly in the matrix.Compared to the phase dissolution rate in two-dimensional condition,the effect of the grain boundary diffusion on dissolution kinetics is more obvious in three-dimensional condition.When phase transformation is dominated by bulk diffusion of solute,the spatial distribution ofαphase is a main factor affecting theαphase dissolution.But when phase transformation is dominated by grain boundary diffusion of solute,the effects of other size distributions on the dissolution ofαphase are not obvious except for uniform PSD.

关 键 词： 晶界扩散 相场模型 溶解 空间分布 尺寸分布

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