摘要
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。
This paper presents an experimental approach to understand dendrite fragmentation of atomised metal alloy droplets during deposition in spray forming, and to seek to quantify the relationship between this dendrite fragmentation behavior and subsequent microstructure evolution. A Gleeble 3500 physical simulator was used to create controlled thermal shock conditions in solid-liquid mixtures of Ni superalloy GH4169 atomised powders, which simulated the environment of droplet deposition during the twin-atomiser spray forming of large diameter GH4169 alloy billets. The experiments supported the hypothesis that the characteristic equiaxed spray formed microstructure depends critically upon the rapid remelting and thermal shock of fine-scale dendrites in solid particles in the spray to provide a high density of solid grains at comparatively high solid fraction.
出处
《钢铁研究学报》
CAS
CSCD
北大核心
2011年第S2期29-32,共4页
Journal of Iron and Steel Research
基金
国家973课题(2010CB631205)
国家自然基金(51074145)
重点实验室基金(9140C4302011021)的资助
关键词
喷射成形
高温合金
组织演变
spray forming
superalloy
microstructure evolution
