Screening of Possible Re-Substitutional Elements in Single-Crystal Ni-Based Superalloys: A Viewpoint From Interdiffusion
- PDF / 4,397,124 Bytes
- 12 Pages / 593.972 x 792 pts Page_size
- 88 Downloads / 155 Views
h-temperature mechanical and physical properties, single-crystal (SX) Ni-based superalloys are widely applied as the main high-temperature parts in aero-engine and turbine blades.[1,2] However, in order to meet the increasing inlet temperature requirements of aero-engine turbines, the high-temperature properties of SX Ni-based superalloys must be further improved. SX Ni-based superalloys have been
developed from the 1st to 6th generation in the past few decades and will continue to evolve in the future. Creep is one of the key factors in controlling the lifetimes of SX Ni-based superalloys at elevated service temperatures. An effective strategy to increase lifetime is to improve creep resistance. As proposed by Reed,[3] in the steady-state regime, for pure nickel the creep strain rate e_ and the diffusion coefficient D of pure nickel are related by e_ ¼
JUAN CHEN is with the Testing Center, Yangzhou University, Yangzhou, 225009 Jiangsu, P.R. China and also with the School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225009 Jiangsu, P.R. China. LIJUN ZHANG is with the State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083 Hunan, P.R. China. Contact e-mail: [email protected] XIAO-GANG LU is with the School of Materials Science and Engineering, Shanghai University, Shanghai 200072, P.R. China. Manuscript submitted August 1, 2018.
METALLURGICAL AND MATERIALS TRANSACTIONS A
2 1 KD ; 3 k5 M
½1
where M is the dislocation multiplication constant, K is a kinetic constant, k is the characteristic dimension of the dislocation sub-structure. As for the creep strain rate e_ in nickel alloys strengthened by solid solution, Cannon and Sherby[4] developed other formulas. When EK0 ADc3:5 r2 , e_ is given by e_ ¼
ADc3:5 r5 E5
½2
Fig. 1—(color on the web) Transition elements adjacent to Re for potential Re-substitutional elements in single-crystal Ni-based superalloys.
Table I.
List of Terminal Compositions of the Diffusion Couples in the Present Work
Couple No.
Composition (Wt Pct)
Temperature (K)
Diffusion Time (ks)
ReC1 ReC2 ReC3 ReC4 ReC5 ReC6 ReC7 ReC8 ReC9 OsC1 OsC2 OsC3 OsC4 OsC5 OsC6 OsC7 OsC8 OsC9 OsC10 IrC1 IrC2 IrC3 IrC4 IrC5 IrC6 IrC7 IrC8 IrC9 IrC10
Ni-2.32 Al/Ni-13.8 Re Ni/Ni-3.28 Al-8.85 Re Ni/Ni-1.75 Al-11.2 Re Ni-2.26 Al/Ni-14.0 Re Ni/Ni-3.18 Al-8.99 Re Ni/Ni-1.61 Al-14.6 Re Ni-2.23 Al/Ni-13.7 Re Ni/Ni-3.38 Al-8.70 Re Ni/Ni-1.69 Al-11.4 Re Ni/Ni-0.90 Al-8.52 Os Ni-1.31 Al/Ni-8.18 Os Ni/Ni-1.79 Al-5.56 Os Ni/Ni-0.88 Al-8.58 Os Ni-1.33 Al/Ni-8.07 Os Ni/Ni-1.75 Al–5.48 Os Ni/Ni-0.89 Al-8.85 Os Ni-1.32 Al/Ni-8.05 Os Ni/Ni-1.75 Al-5.61 Os Ni/Ni-0.89 Al-7.86 Os Ni-3.75 Al/Ni-21.9 Ir Ni/Ni-3.49 Al-14.8 Ir Ni/Ni-1.62 Al-17.0 Ir Ni-3.97 Al/Ni-21.7 Ir Ni/Ni-3.45 Al-16.0 Ir Ni/Ni-1.59 Al-17.3 Ir Ni-3.80 Al/Ni-22.2 Ir Ni/Ni-3.31 Al-14.8 Ir Ni/Ni-1.60 Al-17.9 Ir Ni/Ni-3.37 Al-14.4 Ir
1473 1473 1473 1523 1523 1523 1573 1573 1573 1423 1473 1473 1473 1523 1523 1523 1573 1573 1573 1423 1423 1423 1473 1473 1473 1523 1523 1523 1573
500.4 500.4 500.4 172.8 172
Data Loading...
