TiAl alloys in commercial aircraft engines

Recent progress in the high-cycle fatigue behaviour of γ-TiAl alloys

“…The Paris law of FCG [12] considers the rate of crack growth, da/dN, as a function of the applied stress intensity factor, K = K max − K min , according to da dN = C p K n (1) where C p is a constant, measured crack growth coefficient and n is the dimensionless Paris exponent. On a logarithmic plot (Figure 1), a central, linear section of a sigmoidal FCG dataset exists, beyond the threshold stress intensity K th and before the onset of unstable crack growth at K Ic .…”

“…By mid-2017, the γ -TiAl alloy Ti-48Al-2Cr-2Nb (at.-%) has seen 6 years of commercial flight aboard the GEnx engines (General Electric, U.S.A.) [1]. Pratt & Whittney, with MTU, is also using the third-generation forgeable TNM TiAl alloy in their new geared turbofan engine [1]. For almost three decades, much of the research into these alloys has focused on the low ductility and toughness that limits the tolerance to fatigue crack growth (FCG).…”

“…Gamma titanium aluminide (γ -TiAl) alloys are emerging as a viable lightweight replacement to nickel superalloys, for use in both the turbine and compressor stages of aero-engines [1,2], as well as in high performance automobiles [3] and the nuclear industry [4]. By mid-2017, the γ -TiAl alloy Ti-48Al-2Cr-2Nb (at.-%) has seen 6 years of commercial flight aboard the GEnx engines (General Electric, U.S.A.) [1].…”

Pulvermetallurgische Herstellung von innovativen Hochtemperaturwerkstoffen

“…Die Zusammensetzung von γ-TiAl-Basislegierungen kann wie folgt zusammengefasst werden, wobei die Legierungsgehalte in diesem Artikel in Atomprozent (at%) angegeben sind: Ti-(42-48)Al-(1-3)X1-(1-10)X2-(0-1)X3, wobei X1 = Cr, Mn, V, X2 = Nb, Ta, W, Mo und X3 = Si, B, C, Seltenerdmetalle [2,[4][5][6].…”

“…Generation wurden schon mehrere Elemente hinzulegiert, um den gekoppelten Effekt dieser auszunutzen. Beispiele sind hierfür die von General Electric (USA) entwickelte Ti-48Al-2Nb-2Cr-Legierung, die als Gusslegierung für Turbinenschaufeln in Flugzeugtriebwerken eingesetzt wird [6], oder die von Plansee (Österreich) auf den Markt gebrachte Ti-46.5Al-4(Cr,Nb,Ta,B)-Legierung [7]. Legierungen der 3.…”