Effect of Seed Composition on Single Crystal Growth During LMC Process
Liquid Metal Cooling(LMC)directionally solidified(DS)experiment and numerical simulation were conducted based on seed method using single-crystal superalloy(SX)SX1 and SX2 as materials.The seeds and castings were cut to observe the microstructure of the dendrites.It was found that the complete SX casting can be achieved with the same orientation between casting and seed when the same materials were used in casting and seed.In case of different composition between seed and casting,the complete SX casting can also be obtained with preferred<001>orientation if the liquidus of seed was higher than that of casting.Otherwise DS structure would be found from stray grain formed at meltback interface of seed,which indicated that SX growth was failed.The numerical simulation results show that casting material with higher liquidus than that of seed can solidify preferentially from meltback interface and DS structure formed subsequently during withdrawing.Therefore,it is necessary for orientation control to ensure that the liquidus line of seed is equal to or higher than that of casting during seed method.
liquid metal coolingsingle-crystal superalloyorientation controllingseed method
万方数据
维普
