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本文用金相、电子探针和X射线衍射技术研究了YCo_5、YCo_4Ni、YCo_3Ni_2、YCo_4Cu、YCo_4Al、YCo_(4.8)M_(0.2)(M=Ti、V,Cr、Mn、Fe)化合物在635—800℃范围内的分解行为,发现YCo_5在800℃即发生分解,如果YCo_5中一个Co原子被Ni或Al替代,则降低了分解温度,0.2Co原子被Ti,V、Cr、Mn、Fe替代时,则显著地影响CaCu_5型结构的稳定性。YCo_4Cu在700℃时的分解特征是在晶界和晶粒内部均匀析出(2:17)相。YCo_(4.8)Ti_(0.2)、YCo_(4.8)V_(0.2)和YCo_(4.8)Mn_(0.2)化合物在800℃的分解反应类似于经典的共析分解,然而,YCo_(4.8)Cr_(0.2)和YCo_(4.8)Fe_(0.2)化合物在800℃仅局部分解为(2:17)和(2:7)相,大部分(1:5)相中只析出(2:17)相。
In this paper, the effects of YCo_5, YCo_4Ni, YCo_3Ni_2, YCo_4Cu, YCo_4Al and YCo_ (4.8) M 0.2 (M = Ti, V, Cr, Mn and Fe) 800 ℃. It is found that YCo_5 decomposes at 800 ℃. If one Co atom in YCo_5 is replaced by Ni or Al, the decomposition temperature is lowered. When 0.2Co is replaced by Ti, V, Cr, Mn and Fe , The stability of CaCu_5-type structure is significantly affected. The decomposition of YCo_4Cu at 700 ℃ is that the (2:17) phase precipitates uniformly in the grain boundaries and grains. The decomposition reaction of YCo_ (4.8) Ti_ (0.2), YCo_ (4.8) V_ (0.2) and YCo_ (4.8) Mn 0.2 at 800 ℃ is similar to that of classical eutectoid decomposition. However, the YCo_ (4.8) Cr_ ) And YCo_ (4.8) Fe_ (0.2) only partially decomposed into (2:17) and (2: 7) phases at 800 ℃.