INFLUENCE OF Pt ON THE CREEP RUPTURE PROPERTIES OF Ni-BASED SINGLE CRYSTAL SUPERALLOY

Abstract

The Ni- based single crystal superalloys are considered to be the major materials for advanced areo- engine blades. In order to improve the high temperature properties of Ni- based single crystal superalloys,many refractory elements are introduced into this kind of alloys. Recently Pt has been suggested to be the alloying elements of advanced Ni-based single crystal superalloys. However, there are no researches for the effects of Pt on creep rupture properties of advanced single crystal superalloys. In this work, the influence of Pt element on the creep rupture properties of a Re-containing single crystal superalloy was investigated. The high-temperature creep rupture properties of the Pt-containing Ni-based single crystal superalloy at 1100 ℃, 180 MPa and 1000 ℃, 310 MPa were investigated. The deformation microstructure and the morphology of dislocations were studied by SEM and TEM.The results show that the creep rupture life of Pt-containing superalloy decrease slightly at 1100 ℃, 180 MPa and decreased obviously at 1000 ℃, 310 MPa. The fracture models of different alloys are all ductile fracture, and many irregular microviods and microcracks can be observed in the fracture surfaces. After high temperature creep deformation, regular dislocation networks formed at the g/g' interfaces. The differences of creep rupture properties among those alloys are that Pt element may promote the formation of TCP phase, and the interface between the TCP phase and g matrix may be favorite sites of the initiation of microvoids and microcracks.