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采用Gleeble 3500热模拟机等试验方法研究了喷射成形高温合金GH4169沉积坯内部树枝晶组织向等轴晶组织的演变过程,并对雾化沉积过程中高温合金等轴晶组织的形成机理进行了分析。研究认为,高温合金熔体再辉时产生的热量与飞行熔滴撞击到沉积坯时动能转化产生的热量,造成了喷射成形雾化熔滴中的枝晶重熔,加上熔滴沉积撞击时产生的大量枝晶碎片,在沉积坯半液态层中生成了大量结晶核,是喷射成形高温合金等轴晶组织形成的重要原因。
The evolution of the dendritic structure in the spray-formed superalloy GH4169 was investigated by means of Gleeble 3500 thermal simulator. The formation mechanism of equiaxed grains in the superalloy during atomization and deposition was analyzed . It is considered that the heat generated by the reflow of the superalloy melt and the heat generated by kinetic energy transformation when the flying drop collides with the deposited billet cause the dendrite remelting in the spray forming atomized droplet. In addition, when the droplet deposition impinges A large number of dendritic fragments generated in the semi-liquid deposited billet layer generated a large number of nuclei, spray forming superalloy equiaxed grain structure is an important reason.