【摘要】 用籽晶法制备了沿不同晶体取向凝固的镍基单晶高温合金试样,研究了单晶中枝晶形貌和一次枝晶臂距随凝固取向的变化规律。结果表明:凝固方向偏离[001]取向小于15°时,枝晶排列比较规则,一次枝晶臂距随偏离角度增大而减小;偏离角度为25°时,部分二次枝晶臂阻断了相邻一次枝晶干的生长,导致一次枝晶臂距增大。沿[011]和[111]取向凝固的单晶中由于分别存在2个和3个择优生长的枝晶干,发展出了复杂的枝晶形态。更多还原

【Abstract】 In order to investigate the effect of solidification direction on dendritic morphology and primary dendritic arm spacing(PDAS) in Ni-based single crystal superalloy,seeding technique was applied to obtain the single crystal samples solidified in different orientations.The results indicated that when the deviation degrees from solidification direction to orientation were within 15°,dendrite morphology kept regular and primary dendritic arm spacing declined with deviation degrees increasing;excessively long secondary dendritic arms blocked the growth of vicinal primary dendritic arm when deviation degrees were up to 25°,leading to increase in PDAS.Owing to 2 and 3 dendritic arms orientated in preferential growth direction in crystals solidified in and orientation respectively,complex dendritic configurations are formed.更多还原