摘要
本文采用超高梯度快速定向凝固装置研究了镍基铸造高温合金 K405超细定向柱晶的凝固特性。试验结果表明,当温度梯度为660K/cm 和凝固速率为760μm/s时,可获得超细柱晶体,其一次、二次枝晶间距λ_1和λ_2分别小于25μm 和10μm;Cr,Al,Ti,W,Co 等元素的偏析比均趋近于1;γ′相分布均匀,(γ+γ′)共晶基本消除,MC 碳化物呈点状和小条状沿一次枝晶轴方向均匀分布于枝晶间。
This paper deals with solidification characters of superfine directional columnargrains in cast nickel-base superalloy K405 with rapid directional solidification equipment withsuper-high temperature gradient.Experimetal results show that superfine directional columnargrains have been obtained when solidification rate is equal to 760μm/s.The primary and sec-ondary dendritic spacing λ_1 and λ_2 is less than 25μm and 10μm respectively.The segregation ra-tio of elements Cr,Al,Ti,W and Co tends to unity,γ′particles distribute evenly,eutectic(γ+γ′)is elimiated basically,and MC of dot and thinstrips distribute in interdendritic zone alone pri-mary stem.
基金
国家自然科学基金:9589014
关键词
柱晶
凝固
冷却
镍
合金
航空
superfine directional columnar grains
solidification rate
cooling rate
nickel-base superalloy
