On the role of μ phase during high temperature creep of a second generation directionally solidified superalloy

Effect of Re on the precipitation behavior of μ phase in several single crystal superalloys

“…Topologically close packed (TCP) phases, such as r-, l-, P-or R-phase, are critical to the mechanical properties of the aero engine turbine blades made of nickel-based superalloys and have become very common especially in the new generation superalloys with complicated chemical compositions [1][2][3][4][5][6][7][8]. These phases can deteriorate the mechanical properties of superalloys by depleting the matrix of the refractory alloying elements and reduce their solid strengthening effect, delaminating in the fracture zone and acting as initiation sites for fracture at high temperatures [8][9][10][11][12][13][14][15].…”

Influence of solution temperature on microstructure and creep property of a directional solidified nickel-based superalloy at intermediate temperatures

“…10(c) that, compared to Fig. 3(b), the carbide in the alloy keeps the particlelike configuration, and the elements about 4.88% C, 15.57% B, 17.5% Hf, 15.1% Ta, 10.3% W and 25.1% Cr (atomic fraction, %) are enriched in the particle-like phase according to the SEM/EDS analysis; therefore, it is though that the element B is responsible for the carbide transforming into the particle-like configuration [36].…”

Precipitation behavior of μ phase and creep rupture in single crystal superalloy CMSX-4

“…The high temperature creep properties of recently developed nickelbase single crystal superalloys are mainly improved by introducing large amount of the refractory elements such as Mo, Re and W [7][8][9][10][11], although excessive amount of these elements may render the alloy prone to topologically close-packed phases, such as -, -, P-or R-phase [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Presence of these phases can seriously deteriorate the high temperature mechanical properties of superalloys [7][8][9][10][11][12][13][14][15][16][17]. Firstly, formation of these TCP phases can lead to the depletion of solid solution strengthening elements in the matrix, which becomes more effective in creep conditions and results in severe reduction of the stress rupture life at high temperature [12,13].…”

“…Compared to the other TCP phases, the phase in particular is under the hottest debate, as it presents various morphologies in superalloys and does not always affect the high temperature creep properties of superalloys [12,[14][15][16][17]. Recently, Tian et al reported that Re has an obvious effect on the precipitated morphology of phase during stress/free-stress aging and the strip-like phase promotes the initiation and propagation of the cracks to accelerate the lifetime deterioration of 6% W alloy, while the sphere-like phase formed in 4.5% Re alloy have the double roles of both weakening creep resistance and hindering dislocation movement during creep [12].…”

“…Recently, Tian et al reported that Re has an obvious effect on the precipitated morphology of phase during stress/free-stress aging and the strip-like phase promotes the initiation and propagation of the cracks to accelerate the lifetime deterioration of 6% W alloy, while the sphere-like phase formed in 4.5% Re alloy have the double roles of both weakening creep resistance and hindering dislocation movement during creep [12]. In Wang et al's work, it also shows little adverse effect of the blocky phase on the creep properties of a direction solidified superalloy [14]. To some extent, therefore, the high temperature mechanical properties are dependant on morphologies of the phase.…”