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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 were prepared by selective crystallization and seed-crystal respectively in a high-temperature gradient solidification furnace. The X-ray diffraction (XRD) was used to measure the orientation characteristics of the single crystal. The results show that when the single crystal superalloy is prepared by the method of selective crystallization, the randomly nucleated grains on the cold plate undergo the competitive growth of the crystallizing zone and the crystallization of the helical segment to finally obtain the crystal with the preferred orientation <001> Single crystal. When the single crystal superalloy is prepared by the seed crystal method, the single crystal orientation obtained by the epitaxial growth of the remelted seed crystal is consistent with the seed crystal orientation.