Fe-Ni基合金中次生η相的析出机理

The precipitation mechanism of secondary η phase in a FeNi-based alloy

针对奥氏体合金中次生η相与基体位向关系存在的不同看法，研究了铁镍基奥氏体合金大量次生η相的析出机理，结果表明，η相与基体之间有良好的共格关系：{001}η／／{111}γ，（110）γ／／（210）η．晶界η相首先在一般无规晶界γ＇相处通过不全位错滑移产生堆垛层错带的方式形核，之后通过原子控制长程扩散机制的台阶方式在基体中长大，进入晶界另一侧与之匹配差的晶粒中，晶界随之一起迁动．η相的析出伴随着附近区域γ＇相的溶解和消失．

The precipitation mechanisms of η phase in a FeNi-based alloy were explored. It was revealed that ηphase has a coherent orientation relationship with γ matrix as follows, {001}η//{111}γ, （110）γ//（210）η. The precipitation of η phase proceeded by nucleating at γ＇ phase at random grain boundaries through forming stacking fault layer caused by slip of partial dislocations and by growing in step mode, which was controlled by the long distance diffusion of atoms. The grain boundary migrated with precipitated η phase into the neighbor grain which was incoherent with η phase. The solution and disappearing of γ＇ was caused by precipitation of ηphase.