两种Fe-Ni-Cr系气阀合金中的析出相

PRECIPITATES IN TWO Fe-Ni-Cr VALVE ALLOYS

摘要:

采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)以及X射线衍射仪(XRD)等设备对46Fe-33Ni-15Cr和50Fe-27Ni-20Cr两种气阀合金中的析出相进行了研究,结果表明,固溶时效后,46Fe-33Ni-15Cr合金中有γ"相、σ相和MC相,而50Fe-27Ni-20Cr合金中有γ"相、σ相、MC相和Laves相；46Fe-33Ni-15Cr合金中的γ"相有球状和胞状两种形态,50Fe-27Ni-20Cr合金中的γ"相都呈球状,尺寸略小,约为20nm~40nm；46Fe-33Ni-15Cr合金中的σ相成条状沿晶界分布,50Fe-27Ni-20Cr合金中的σ相呈针状与晶界呈一定位向分布。在700℃时效2000小时,随着时效时间的延长,46Fe-33Ni-15Cr中的σ相数量增长幅度远大于50Fe-27Ni-20Cr。

Abstract:

The scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were adopted to investigate precipitates in 46Fe-33Ni-15Cr and 50Fe-27Ni-20Cr valve alloys. The results show that 46Fe-33Ni-15Cr alloy contains γ", σ and MC phase after solution and aging, however 50Fe-27Ni-20Cr alloy contains γ", σ, MC and Laves phase. The γ" phase has two patterns, spherical and cellular in 46Fe-33Ni-15Cr alloy. But only one pattern of γ" phase spherical exists in 50Fe-27Ni-20Cr alloy, and its size is about 20nm~40nm,smaller than that in 46Fe-33Ni-15Cr alloy. The σ phase distributes in strip on the grain boundary in 46Fe-33Ni-15Cr alloy, but it precipitates in needle shape along the grain boundary in a certain orientation. Within 2000 hours aging under 700℃, the amount of σ phase in 46Fe-33Ni-15Cr increases more rapidly than that in 50Fe-27Ni-20Cr alloy with the increasing aging time.