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采用籽晶法控制晶体取向,研究了不同抽拉速率下镍基高温合金汇聚型双晶的竞争生长.结果表明,低抽拉速率下,非择优枝晶能够穿插进入择优枝晶间的液相通道,抑制择优枝晶的生长,使晶界向择优晶粒方向偏移.高抽拉速率下,非择优枝晶几乎全部被晶界择优枝晶阻挡,晶界与择优枝晶干平行.非择优枝晶进入择优枝晶间的液相通道使择优枝晶萎缩消失是非择优晶粒淘汰择优晶粒的主要因素,并以此提出了抽拉速率对竞争生长的影响机制.
The crystal orientation was controlled by the seed crystal method, and the competition growth of nickel-based superalloy converging bimorphs under different drawing rates was studied. The results show that the non-preferred dendrites can interspersed into the liquid phase Channel, which inhibits the growth of the preferred dendrite and shifts the grain boundary to the direction of the preferred grain. At high draw rates, the non-preferred dendrites are mostly blocked by the preferred grain boundaries and the grain boundaries are parallel to the preferred dendrites The merit of the dendrite into the meso-dendrite liquid channel between the preferred dendritic atrophy disappear is the non-preferred grain out of the main factors to eliminate the preferred grain, and thus the drawing rate of competitive growth mechanism.