35

Technical Review

Trend of Heat Resistant Alloys for Aero Engine Applications

Nobuhiro Miura

Synopsis

2012 5 17 Dr., Eng., National Defense Academy, School of Systems Engineering,

Department of Mechanical Systems Engineering

1/3 Fig. 1 SFC

Specific Fuel Consumption 56

SFC

In recent years, with emission reduction of carbon dioxide and nitrogen oxide, higher output and effciency of civil aircraft engines are demanded. They have been done by improvement of thermal and propulsive efficiencies. The thermal efficiency of the aircraft engine strongly depends on the turbine inlet temperature (TIT). With an increase in TIT, hot section parts in the engines such as combustion chambers, turbine blades, nozzle guide vanes, discs and shafts are expected to endure higher temperatures. Ni-based superalloys have been used for the hot section parts because of their excellent high-temperature strength, ductility, thermal fatigue and oxidation resistance. Recent alloy design of Ni-based superalloys has focused on increasing the temperature capability through the addition of Rhenium and Ruthenium. For the next-generation engines, further lightweight of the heat-resistant alloys has been demanded and practical use of ceramics matrix composites is expected as materials beyond Ni-based superalloys. In this paper, the latest developing trend of the heat-resistant alloys is outlined.

1

Ti

1 3

B787-8

20 %

4

50 %

83 1 2012 36

Fw

Fw = Fn / W 5

Fw 1 W

Fw W

6 7

15

o

SFC o

3Ni31

TIT:

Turbine Inlet Temperature

TIT Fig. 2 TIT 8

TIT TIT

SFC

Fig. 3 TIT 910

1950 TIT 900

TIT

10

1600

TIT 2000 11TIT

2

1930

40

1 PWR Qf

th

th = PWR / Qf 1

2 Fn

Va PWRpp = Fn Va / PWR 2

3

oo = th p 3

3

Fn

SFC

SFC = Wf / Fn 4

Wf

SFC

Fig. 1.Improvement of SFC of aero gas turbine engines.56

37

1

1

Ni

Ni

Ni

TBC: Thermal Barrier Coarting

12 14

32NiNi

CC:

Conventional Casting1970

DS: Directional Solidification

SC: Single

Crystal

Ni

Ni3AlTi

SEM

Fig. 4

Fig. 2.Relation between pressure ratio and turbine inlet temperature.8

Fig. 4SEM of as-heat treated single crystal Ni-based superalloy CMSX-4.

Fig. 3. Evolution of TIT of aero gas turbine engines.

DS

BZr

83 1 2012 38

Table 1. Chemical compositions of single crystal Ni-based superalloys wt%

.

Table 1 Re

1970 DS

50PWA1480Rene N4 CMSX-2

1

Re

1 Re 3wt%

PWA1484Rene N5CMSX-4 2

2

1 25

Re 5 6 wt% CMSX-10ReneN6

3 1050

Re Ru 2 3 wt% 4

GE SENCMA NIMS

15 4

Ru 1100

5 TMS-162 TMS-196 NIMS

16 18

39

33

Re

Ru 17 19Re

6

2011

6 3,000 4,000 kg

Re Cu

Mo 20

CuMo

ReRu

GE

2 Ni ReneN5

Re 1.5 wt% Rene N515

Rene N500 Rene N5

Rene N515

Re

Fig. 521 B737 A320

CFM56

22

Fig. 6 2 CMSX-4 1273 K[001]

Re NKH71

CMSX-4

160 MPa

[001]

100

23

CMSX-4

24

NKH71 CMSX-4

CMSX-4 /

Fig. 7

NKH71 /

4 TMS-138

Fig. 5.Comparison with creep rupture property of Rene N5 and Rene N51521.

Fig. 6.Stress-time to rupture curves of CMSX-4 and NKH71 at 1273 K.

83 1 2012 40

4

p Va

0.9

BPRBy-Pass Ratio BPR = Waf / Wap

Waf Wap

BPR 10

BPR SFC

Re

15

BPR TIT

Fig. 8 GE90-115B 25

B777-300ER

GE90-115B GE

IHI GE1014

B787 B747-8I GE

GEnx

3 B787 TRENT1000

70

5 51TiAl

Fw

Fig. 7.Dislocation substructure at / interface of creep interrupted specimens a CMSX-4 and b NKH71.

Fig. 8.Appearance of GE90-115B low pressure turbine shaft.25

41

Ni

GEnx

7

2 TiAl

Fig. 926TiAl

Fig. 9. TiAl low pressure turbine blade.26

Fig. 10. Appearance of CMC afterburner nozzle flap.2952NiTIT

Ni

CMC: Ceramics Matrix

Composite SiC Al2O3

SiC Ni

1/3 1200

3 1300

222728

CMC

Fig. 10 29.

6

%

NOx

TIT

NOx

TIT

83 1 2012 42

NOx

1386

264120072135620065884 http://www.newairplane.com/787/design_highlights/#/

Home

5 7

200342

62004139

7

2005p.229

8 7

200352

9 123

38199724710 123

48200736511 123

38199715712 123

4820073391338201014614 38

2010155

15

16201171716 A. SatoH. HaradaA.-C. YehK. KawagishiT.

KobayashiY. KoizumiT. Yokokawa and J. X. Zhang

: Superalloys20082008131

17 H. Harada 123

48200735718 A. SatoA.-C. YehT. KobayashiT. Yokokawa

H. HaradaT. Murakumo and J. X. Zhang : Energy

Materials2200719

19 X.P. TanJ.L. LiuT. JinZ.Q. HuH.U. HongB.G.

ChoiI.S. Kim and C.Y. Jo : Mat. Sci. Eng. A52820118381

2039201123421 P. J. FinkJ.L. MillerD. G. Konitzer : JOM62

201055

22

20101

23 N. MiuraY. Kondo and N. Ohi : Superalloys2000

2000377

24 N. MiuraY. Kondo and T. Matsuo : Proc. of 9th Int.

Conf. on Creep and Fracture of Engineering Materials and

Structures2001437

25 802009127

26 IHI

48200815327 J-Y. Guedou : Proc. of the 27th Int. Cong. of the

Aeronautical Sciences20101

2838201014029 Aviation Week & Space TechnologyMarch 92009

36