研究了基材热处理态和激光扫描速率对多道沉积DD5单晶高温合金沉积道内的杂晶(SGs)形核位置及数量的影响,探讨了不同条件下杂晶的形成机理。结果表明,当激光扫描速由5mm/s增大到20mm/s时,沉积道顶部的柱状晶-等轴晶转变(CET)导致杂晶数目减少;采用固溶方式处理基材时,沉积道底部杂晶的尺寸和数量较铸态基材的明显减小;沉积道之间的相互搭接不会产生新的杂晶;当采用固溶态基材、激光扫描速率为20mm/s时,基本可以得到无杂晶的多沉积道搭接界面。 The effect of substrate heat treatment and laser scanning rate on the location and number of impurity-like (SGs) nucleation in DD5 monocrystalline superalloy deposition lanes was investigated. The formation mechanism of stray crystals under different conditions was also discussed. The results show that when the laser scanning speed increases from 5 mm / s to 20 mm / s, the columnar crystal-equiaxed crystal transition (CET) at the top of the deposition channel leads to the decrease of the number of the stray grains. When the substrate is treated by solution treatment, The size and number of the bottom of the miscellaneous crystal than the as-cast substrate significantly reduced; lap deposition between the lap will not produce new hybrid crystals; when using solid-state substrate, the laser scanning rate of 20mm / s, Basically, you can get a non-miscellaneous multi-deposition Tao lap interface.