K5合金高梯度下快速凝固定向组织的研究

Study on Directionally Solidified Microstructure of Superalloy K5 under High tem perature Gradient and Rapidly

本文利用自行研制的超高梯度定向凝固装置（ＺＭＬＭＣ），考察镍基高温合金Ｋ５在不同的凝固速率下特别是在高速下定向组织的生长行为。研究表明，利用该定向凝固装置可获得完全细化的定向超细晶组织。当Ｒ＝６００ｃｍ／ｓ时，其一次间距λ１小于２３８μｍ；二次枝晶间距被强烈抑制，λ２仅为６６μｍ，组织更加均匀．另外。

Nickel base superalloy K5 w as directionally solidified to study the developm ent of m i crostructure under super high tem perture gradient and rapided cooling. The results of the experim ent showthat the surper fine directionalsolidified structures are obtained w ith super tem perature gradientand surper cooling rate w hen solidification rate arrives 600μm /s: The prim ary arm spacing λ1 is less that 23 8μm ; Thesecondary arm spacing λ2 is less than 10μm . In addition,the interface stability theory is discussed under theexperim ental condition.