钇抑制FeCrAl合金脆性的作用与合金中铬、钇含量的关系

Relations between the Actions of Yttrium InhibitingBrittleness and the Contents of Chromium andYttrium in FeCrAl Alloys

Ｆｅ－（１５～２５）Ｃｒ－（４～５）Ａｌ合金在９００～１３００℃加热后发生高温脆化，脆化的温度－时间关系曲线与双曲线相似，在４００～５４０℃时效后发生４７５℃脆化，脆化曲线由一次脆化的“双曲线”和二次脆化的“Ｃ曲线”组成．在含０．２％～１．４％Ｙ的ＦｅＣｒＡｌ合金中，由于Ｙ－Ｆｅ相粒子俘获碳原子的作用，高温脆化和４７５℃脆化受到强烈抑制。时效时ａ相析出过程的发展使合钇合金抵抗脆化的能力随铬含量升高而降低。合金的抗脆化性能随钇含量升高而提高，含０．３％～０．４％Ｙ时最高。

High temperature embrittlements occur when Fe-(15-25)Cr-(4-5)Al alloys are heatedat 900 - 1300 . The temperature relation curves of the embrittlements are similar tohyperbola. 475 embrittlements after aging at 400-540. The embrittlement curves consistof two group curves-one of them is similar to'hyperbota'and another to'C curves'. In FeCrAlY alloys with 0.2% - 1.4%Y, the high temperature embrittlements and the 475 embrittlements are inhibited strongly, as a result of the action of Y-Fe phase capturing Carbon atoms in a-phase. However, owing to the development of Cr-rich a-phase precipitation process, the embrittlement-resistance inthe alloys with yttrium decreases with the increase in chromium content. The embrittlement-resistanceincreases with the increase of yttrium content and become the highest in the alloys with 0.2%-0.4%Y.