摘要:
利用金相显微镜(OM)和扫描电镜(SEM)对含铒不锈钢中第二相的析出行为进行了研究。结果表明:不锈钢中第二相以Ni-Er系为主,存在两种元素组成一致但含量差异明显的第二相,两种第二相中Ni、Er摩尔分数之比均为2∶1;不锈钢中第二相大部分呈长条状,沿晶界呈网状析出,其析出数量随着Er含量的增加呈直线上升的趋势,当Er含量由1.62%增加至7.45%时,第二相的析出面积百分数由7.0%增至24.5%;第二相塑性较基体组织差,两者无法协同变形,外力作用导致第二相破碎、断裂,从而引起了微裂纹的萌生和发展。
Abstract:
The precipitation behaviors of the second phase in Er-containing stainless steel were investigated by means of optical microscope（OM） and scanning electron microscope（SEM）.The second phase in stainless steel is mainly Ni-Er system,there are two second phases with the same elements but showing obviously different content,and the molar fraction ratio of Ni and Er in the two second phases is 2∶1.Most of the second phases in stainless steel are rod-like and precipitate along the grain boundaries,their amounts increase linearly with increasing the Er content.When the mass fraction of Er increases from 1.62% to 7.45%,the area percentage of the second phase increases from 7.0% to 24.5%.The plasticity of the second phase is worse than that of the matrix,thus the two phases cannot deform synergistically.Consequently the external force causes the second phase to break and fracture,which leads to the initiation and development of micro-cracks.
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