微量元素Si对K452镍基铸造高温合金组织和力学性能影响的研究

Effects of Trace Element Si on Microstructure and Mechanical Properties of K452 Ni-based Cast Superalloy

摘要: 研究了Si元素含量对K452镍基铸造高温合金标准热处理态微观组织形貌、拉伸和持久性能的影响。通过OM、SEM和EDS等表征及力学性能测试,发现在K452镍基铸造高温合金中,Si的添加量对碳化物形貌和分布有很大影响。由于Si元素含量的提高,分布于晶界上的碳化物数量随之增多。Si对拉伸强度的影响和Si的添加多少有关,低于0.5wt%的Si对合金抗拉强度影响不明显,可是Si添加量大于1.0wt%时,合金的抗拉强度明显减小。合金在900℃/200 MPa条件下持久寿命随着Si含量的增加而显著降低。

Abstract: The effects of different Si additions on the microstructure, tensile properties and stress rupture properties of K452 Ni-based cast superalloy after standard heat treatment were studyied. Using OM, SEM, EDS and other experimental methods, the following results are obtained: in K452 Ni-based cast superalloy, the addition of Si has a great influence on the morphology and distribution of carbides. Due to the increase of Si content, the number of carbides distributed on the grain boundary increases. The effect of Si less than 0.5wt% on the tensile strength of the alloy is not obvious, but the tensile strength of the alloy decreases significantly when the amount of Si is greater than 1.0wt%. The stress rupture life of the alloy at 900 ℃/200 MPa decreases obviously with the increase of Si content.