Nb在高Ti中Al铁基高温合金的作用

Effect of Niobium on Ferrous Base Superalloy with High Titanium and Medium Aluminium

探讨Nb在高Ti中Al铁基高温合金的作用,认为Nb参与了γ'-相形成,增加γ'-相数量,生成Ni3(Al、Ti、Nb)提高γ'-相的固溶温度,从而实现第二相强化。同时,Nb促使碳化物相处于均匀弥散分布状态使合金组织均匀化并显著提高室温、700℃拉伸和持久强度,改善塑性。当Nb含量超过1.38%时γ'-相析出达到平衡,μ-相结构发生变化,且数量增加,晶界小颗粒状、块状、链状、μ相析出脆化了晶界,降低合金塑性。

Effect of niobium on ferrous base superaUoy with high titanium and medium aluminium was discussed and investigated, the results showed that niobium improved the formation of γ-phase, increased the amount of γphase, formed Ni3（ Al, Ti, Nb） and raised the solid solution tetnperature , with the result that a two - phase strengthening was realized. In addition, niobium made the carbide phase stay in the status of uniform dispersion, made the metallographic homogenizing and improed the tensile and rupture strength at room temperature and 700℃. As the niobium content exceeds 1.38%, precipitation ofγphase got the balance, the structure of μ phase changed, its amount increased. Fine grain, massive structure, chain structure and precipitation ofμphase resulted in brittlement and decreased alloy plasticity.