Ru对镍基单晶高温合金高温持久性能的影响

摘要

在真空定向炉中浇注了具有[001]方向的不含Ru和含Ru两个单晶高温合金,其它合金元素的含量基本相同,研究Ru对单晶高温合金在(980℃,250 MPa),(1100℃,140 MPa)和(1120℃,140 MPa)条件下持久性能的影响.结果表明,加入Ru能提高单晶高温合金的高温持久性能,提高作用随着温度的升高而降低.在断裂后的两种合金试样中都观察到γ'相定向粗化和筏排化,并且在(1100℃,140 MPa)和(1120℃,140 MPa)条件试样中有针状的TCP相析出,而在(980℃,250 MPa)条件试样中无TCP相析出.加入Ru减少了TCP相的析出数量.最后,讨论了加入Ru带来的合金组织变化进而提高合金持久性能的原因.%Two experimental single crystal superalloys,Ru-free alloy and Ru-containing alloy with[001]orientation,other alloying element contents being basically kept same,were cast in the directionally solidified furnace.The effect of Ru on the stress rupture properties of the single crystal superalloy was investigated at(980 ℃,250 MPa),(1100 ℃,140 MPa)and(1120 ℃,140 MPa).The results show that Ru can enhance high temperature stress rupture properties of single crystal superalloy.The improvement effect of Ru addition on stress rupture properties decreases with increasing test temperature.The γ'coarsening and rafting directionally are observed in Ru-free alloy and Ru-containing alloy after stress rupture test.Needle shaped TCP phases precipitated in both of alloys after stress rupture test at(1100 ℃,140 MPa)and(1120 ℃,140 MPa)and no TCP phase was observed in both of alloys after stress rupture test(980 ℃,250 MPa).The precipitate volume fraction of TCP phases is significantly decreased by the addition of Ru.At last,the relationship between the microstructure change with Ru addition and improvement of stress rupture properties was discussed.