scholarly journals Microstructure Evolution and Mechanical Properties of Novel γ/γ′ Two-Phase Strengthened Ir-Based Superalloys

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1171
Author(s):  
Xiao Fang ◽  
Rui Hu ◽  
Jieren Yang ◽  
Yi Liu ◽  
Ming Wen
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Microstructure Evolution ◽  
Quaternary Alloys ◽  
Two Phase ◽  
Solid Solution Strengthening ◽  
New Class ◽  
High Temperature Mechanical Properties ◽  
Evolution Phase ◽  
Ultrahigh Temperature

Ir-based superalloys are irreplaceable in some specific harsh conditions regardless of their cost and high density. In order to develop a new class of Ir-based superalloy for future ultrahigh-temperature applications, the microstructure evolution, phase relationships, and mechanical properties of Ir–Al–W–Ta alloys with γ/γ′ two-phase structure were investigated. Room- and high-temperature compressions at 1300 °C, and room-temperature nanoindentation for the Ta-containing Ir–6Al–13W alloys were conducted. The results show that the addition of Ta can significantly improve the high-temperature mechanical properties, but does not change the fracture mode of the Ir-based two-phase superalloys. The compressive strength of quaternary alloys can be attributed to the precipitation of γ′-Ir3(Al, W) phase and solid solution strengthening. The microstructure and mechanical properties of Ir–Al–W–Ta quaternary alloys exhibit promising characteristics for the development of high-temperature materials.

Phase equilibrium and mechanical properties of Cr-Mo-Nb-Si-B alloys Composed of BCC and T2-silicide phase

MRS Advances ◽  
2019 ◽  
Vol 4 (25-26) ◽  
pp. 1491-1496 ◽  
Author(s):  
Daisuke Goto ◽  
Ken-ichi Ikeda ◽  
Seiji Miura
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Phase Equilibria ◽  
Power Plants ◽  
Thermal Power ◽  
Silicide Phase ◽  
Two Phase ◽  
New Class ◽  
High Temperature Materials ◽  
Si Content

ABSTRACTA new class of high-temperature materials based on refractory elements was investigated with an aim to improve the energy efficiency of thermal power plants. Alloys based on Nb and Mo composed of BCC solid solution (BCCss) (Nb-Mo) and T2-silicide (Nb,Mo)5(Si,B)3 are promising candidates as high-temperature materials. Further investigation on the alloy phase equilibria of this system is required to improve the mechanical properties and oxidation resistance through optimization of the phase compositions. Cr is one candidate to modify the properties of the alloy because Cr is expected to stabilize the T2 compound phase along with B. Here, the phase equilibria among BCCss and the T2 compound are widely investigated in the Cr-Mo-Nb-Si-B system, and a BCCss-T2 two-phase microstructure is found in Mo-rich alloys. The B/Si ratio in the T2 phase increases with the Cr content, while almost no B solubility was found in BCCss. As the Si content increases in alloys, the A15 silicide phase ((Cr, Mo, Nb)3Si) and/or Laves phase appear.Nanoindentation tests were conducted to investigate the mechanical properties of the BCCss phase of the alloys in the Cr-Mo-Nb-Si-B system. The nanohardness and reduced elastic modulus of these alloys tended to be higher with an increase in Cr.

Strength and Toughness of Be12Nb, Be17 Nb2 and Two-Phase Be12Nb-Be17Nb2

1992 ◽  
Vol 273 ◽  
Author(s):  
Stephen M. Bruemmer ◽  
Bruce W. Arey ◽  
Charles H. Henager
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperature ◽  
Intermetallic Compounds ◽  
Compression Strength ◽  
Bend Strength ◽  
Two Phase ◽  
High Temperature Mechanical Properties ◽  
Strength And Toughness

ABSTRACTBend strength, compression strength, and fracture toughness of niobium beryllide intermetallic compounds have been assessed at temperatures from ambient to 1200°C. Hot-isostatically-pressed (HIP) Be12Nb showed significantly improved lowand high-temperature mechanical properties over vacuum-hot-pressed (VHP) material. Strengths at 20°C were 250 MPa in bending and 2750 MPa in compression with a fracture toughness of ∼4 Mpa√m, much higher than previously measured for this compound. High-temperature (≥ 1000°C) mechanical properties were also improved with bend strengths of 250 MPa at 1200°C as compared to only 70 to 100 MPa for the VHP material. However, severe pest embrittlement was detected in the HIP material at temperatures between 650 and 1000°C.

Effects of Nb on the High Temperature Mechanical Properties of TiNiAl Alloys

2007 ◽  
Vol 546-549 ◽  
pp. 1477-1480 ◽  
Author(s):  
Gao Song Qiu ◽  
Xin Qing Zhao ◽  
Ling Jie Meng ◽  
Hui Bin Xu
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Yield Strength ◽  
Yield Stress ◽  
Microstructure Evolution ◽  
High Yield ◽  
Strengthening Effect ◽  
High Temperature Mechanical Properties ◽  
Solution Strengthening ◽  
Nb Addition

A series of NiTiAl based alloys with different amount of Nb addition were prepared and the effects of Nb on both the mechanical properties and microstructure evolution were investigated. The addition of Nb can remarkably enhance the high temperature yield strength of these alloys. The highest yield strength of the alloys with 10 at% Nb reaches 1237MPa at 873K and 875MPa at 973K, respectively. The Ti2Ni(Al,Nb) precipitates and the solution strengthening effect might be responsible for the high yield stress achieved at high temperature.

Effect of а Number of Transition Metals on the Cohesive Properties of Cr-Ni-Base Alloys

2016 ◽  
Vol 879 ◽  
pp. 1998-2002 ◽  
Author(s):  
V.N. Butrim ◽  
V.I. Razumovskiy ◽  
A.G. Beresnev ◽  
A.S. Trushnikova ◽  
I.M. Razumovskii
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
High Temperature ◽  
Ab Initio Calculations ◽  
Base Alloy ◽  
Two Phase ◽  
Alloying Additions ◽  
High Temperature Mechanical Properties ◽  
Cohesive Properties ◽  
Theoretical Predictions

We used the results of ab initio calculations to improve the high temperature mechanical properties of a Cr-Ni-base alloy (Cr-33Ni-2W-0,3Ti-0,3V, wt.%) (alloy I) with two-phase α - γ microstructure. It was established that γ – phase in Cr-Ni-base alloy (I) plays a key role in the processes of plastic deformation. By analogy with Ni-base superalloys the bulk and grain boundaries cohesion in γ – phase of the Cr-Ni-base alloy (I) were strengthened by adding a package of the “low alloying” elements (Zr, Hf, Nb, Ta) (alloy II) chosen in accordance with our theoretical predictions. We further investigated an influence of a sum (Ta, Nb, Hf, Zr) like the low alloying additions on the mechanical properties of Cr-Ni-base alloy (I). The results of mechanical testing revealed a significant strengthening of the alloy (II) in comparison with (I) at the temperature 1080 oC in accordance with our predictions. We also investigated the microstructure’s peculiarities of the alloys (I) and (II).

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