不同制备方法对单晶高温合金取向特征的影响（英文）

Orientation Characteristics of Single Crystal Superalloys with Different Preparation Methods

在高温度梯度定向凝固炉中分别采用选晶法和籽晶法制备单晶高温合金,并采用XRD测定单晶的取向特征。结果表明,采用选晶法制备单晶高温合金时,在激冷板上随机形核的晶粒经过起晶段的竞争生长和螺旋段的选晶作用后,最终获得具有择优取向<001>的单晶。采用籽晶法制备单晶高温合金时,通过重熔籽晶的外延生长,所获得的单晶取向与籽晶取向保持一致。

Single crystal superalloys have been prepared separately by a grain selector and a seeding technique in a high temperature gradient directional solidification furnace. The orientation characteristics were measured by XRD. Results indicate that for the grain selector method, the crystal solidification begins at the cooling plate with random nucleation, and through mutual competitive growth at the starter block. The grains enter the spiral selector, and finally the single crystal superalloys which are close to 〈001〉 direction are obtained. By the seeding technique, by epitaxial growth of partially melted seed crystals, single crystal superalloys which have the same orientation as the seed crystal are obtained.