Influence of Ru on the Microstructure of Ni-Base Single Crystal Superalloys

2011 ◽  
Vol 306-307 ◽  
pp. 562-571 ◽  
Author(s):  
Fei Sun ◽  
Jian Xin Zhang
Keyword(s):  
Single Crystal ◽  
Volume Fraction ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Solid Solution Strengthening ◽  
Refractory Elements ◽  
Tcp Phases ◽  
Solution Strengthening ◽  
Strengthening Element ◽  
Partitioning Behavior

Addition of Ru in Ni-base single crystal superalloys had been used to improve the elevated temperature strength and other multiple properties. Significant decreases in stacking fault energy of the γ phase and the volume fraction of γ′ phase are observed with the addition of Ru. As well as serving as an effective solid-solution strengthening element in high refractory content Ni-base single crystal superalloys, Ru additions are able to effectively strengthen both the γ and γ′ phases and suppress the formation of TCP phases. Due to the changes in the partitioning behavior of elements and the slight decrease in the supersaturation of refractory elements in γ phase associated with Ru additions, high temperature creep resistance and the microstructural stability of the alloy are improved remarkable. The influence of Ru on the microstructure of Ni-base single crystal superalloys is reviewed.

Role of Cobalt in the Microstructural Stability of Single Crystal Superalloys

2016 ◽  
Vol 849 ◽  
pp. 557-562 ◽  
Author(s):  
Jing Yang Chen ◽  
Qing Li ◽  
Jie Li ◽  
Xin Tang ◽  
Cheng Bo Xiao
Keyword(s):  
Single Crystal ◽  
Volume Fraction ◽  
Thermal Exposure ◽  
Precipitate Size ◽  
Microstructural Stability ◽  
Tcp Phases ◽  
The Stability ◽  
Co Addition ◽  
Good Agreement

The effects of Co additions on the evolution of γ' precipitates and topologically close-packed (TCP) phases during thermal exposure at 950 °C were investigated for two Ni-based single crystal superalloys with 7.9 wt.% Co and 9.1 wt.% Co. The results indicated that the γ′ morphology was not affected by Co content, whereas γ′ volume fraction decreased and precipitate size increased due to lower Co addition after standard heat treatment. The coarsening of γ′ precipitates in both alloys was controlled by diffusion. The γ′ coarsening rate increased, while the stability of γ′ volume fraction decreased due to lower level of Co addition during 950 °C thermal exposure because more Co addition suppressed the diffusion process. High Co addition promoted the formation of μ phase after thermal exposure at 950 °C for 1000 h due to higher γ′ volume fraction, more stable γ′ volume fraction and higher electron vacancy number. The experimental results of μ phase precipitation showed good agreement with thermodynamic calculation by JMatPro.

Microstructural characterization of a rapidly solidified Al-Fe-V-Si alloy for elevated temperature applications

1988 ◽  
Vol 46 ◽  
pp. 550-551
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Grain Growth ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Temperature Applications

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.

scholarly journals The Importance of Diffusivity and Partitioning Behavior of Solid Solution Strengthening Elements for the High Temperature Creep Strength of Ni-Base Superalloys

2020 ◽  
Vol 51 (12) ◽  
pp. 6195-6206 ◽  
Author(s):  
S. Giese ◽  
A. Bezold ◽  
M. Pröbstle ◽  
A. Heckl ◽  
S. Neumeier ◽  
...  
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Creep Resistance ◽  
Elevated Temperatures ◽  
Solid Solution Hardening ◽  
Stress Regime ◽  
Solid Solution Strengthening ◽  
Solution Strengthening ◽  
The Individual ◽  
Partitioning Behavior

AbstractThe creep resistance of single-crystalline Ni-base superalloys at elevated temperatures depends among others on solid solution strengthening of the γ-matrix. To study the influence of various solid solution strengtheners on the mechanical properties, a series of Ni-base superalloys with the same content of different alloying elements (Ir, Mo, Re, Rh, Ru, W) or element combinations (MoW, ReMo, ReW) was investigated. Nanoindentation measurements were performed to correlate the partitioning behavior of the solid solution strengtheners with the hardness of the individual phases. The lowest γ′/γ-hardness ratio was observed for the Re-containing alloy with the strongest partitioning of Re to the γ-matrix. As a result of the creep experiments in the high-temperature/low-stress regime (1373 K (1100 °C)/140 MPa), it can be concluded that solid solution hardening in the γ-phase plays an essential role. The stronger the partitioning to the γ-phase and the lower the interdiffusion coefficient of the alloying element, the better the creep resistance. Therefore, the best creep behavior is found for alloys containing high contents of slow-diffusing elements that partition preferably to the γ-phase, particularly Re followed by W and Mo.

Topologically Close-Packed Phase Precipitation in Ni-Based Superalloys

2011 ◽  
Vol 320 ◽  
pp. 26-32 ◽  
Author(s):  
Fei Sun ◽  
Jian Xin Zhang
Keyword(s):  
Alloy Composition ◽  
Rupture Life ◽  
Precipitation Trend ◽  
Phase Precipitation ◽  
Microstructural Stability ◽  
Creep Properties ◽  
Refractory Elements ◽  
Topologically Close Packed ◽  
Tcp Phases ◽  
Comprehensive Performance

The addition of refractory elements is effective in improving the comprehensive performance of Ni-based superalloys, and meanwhile, the precipitation trend of TCP phases increases with the elements content due to the segregation of refractory elements during high temperature service. The precipitation of TCP phases obviously decreased the creep properties and creep rupture life of superalloys. The toughness and plastic of superalloys also dramatically deteriorated. The addition of Ruthenium (Ru) is shown to suppress the formation of TCP phases in Ni-based superalloys, resulting in much improved the creep resistance and the microstructural stability. The studies on TCP phases in Ni-based superalloys including crystallography and precipitation of TCP phases and the effect of alloy composition on TCP phases are reviewed.

The Influence of Secondary Phase on Impact Toughness of Alloyed Iron Aluminides

2020 ◽  
Vol 405 ◽  
pp. 145-150
Author(s):  
Martin Švec ◽  
Adam Hotař ◽  
Věra Vodičková ◽  
Vojtěch Keller
Keyword(s):  
Impact Toughness ◽  
Room Temperature ◽  
Volume Fraction ◽  
Fracture Behaviour ◽  
Secondary Phase ◽  
Iron Aluminides ◽  
The Other ◽  
Secondary Phases ◽  
Solid Solution Strengthening ◽  
Solution Strengthening

The microstructure and fracture surfaces were investigated for five Fe3Al – based iron aluminides doped by different alloying elements (Nb, Zr + C, Cr) or without addition. Generally, iron aluminides are considered as brittle material at room temperature, therefore the type and distribution of secondary phases affect the fracture behaviour. The influence of present secondary phase particles on impact toughness at room temperature was evaluated in comparison to binary alloy. The type and the volume fraction of particles affect the value of impact toughness significantly – these values decrease with increasing volume fraction of precipitates. On the other hand, the solid solution strengthening improves impact toughness.

Physical and Mechanical Properties of Two-Phase Zr-Cr-Mn Alloys

1998 ◽  
Vol 552 ◽  
Author(s):  
A. Goldberg ◽  
D. E. Luzzi
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Physical And Mechanical Properties ◽  
Laves Phase ◽  
Two Phase ◽  
Tem Analysis ◽  
Atomic Size ◽  
Solid Solution Strengthening ◽  
Solution Strengthening ◽  
Mn Content

ABSTRACTThe Zr-Cr-Mn system is used to explore the effect of a lowered SFE on the room temperature mechanical properties of a Laves phase using elements of similar atomic size. The ternary Zr-Cr-Mn diagram in the region from 0 to 12 at. % Mn is first determined and it is shown that Mn substitutes only for Cr in the Laves phase. TEM analysis of the density of stacking fault energy related defects such as annealing twins indicates that Mn substitution for Cr in ZrCr2 lowers the SFE of the cubic Laves phase. Mechanical testing of the two phase alloys is used to explore the effects of Mn content and the volume fraction of each phase on the ductility and fracture behavior in compression. It is found that the mechanical properties are well-described by a model incorporating solid solution strengthening in a ductile-brittle two phase alloy.

Effects of Ruthenium on Microstructure and Stress Rupture Properties of a Nickel-Base Single Crystal Superalloy

2013 ◽  
Vol 747-748 ◽  
pp. 777-782
Author(s):  
Shuai Yang ◽  
Jian Zhang ◽  
Yu Shi Luo ◽  
Yun Song Zhao ◽  
Ding Zhong Tang ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Stress Rupture ◽  
Thermal Exposure ◽  
Microstructural Stability ◽  
Stress Rupture Properties ◽  
Tcp Phases ◽  
Mean Size ◽  
Nickel Base ◽  
Rupture Properties

The effect of Ru addition (0 wt.%, 3 wt.%, 5 wt.%), on γ morphology, elemental segregation, microstructural stability under long-term thermal exposure at 980 and stress rupture properties at 1100°C/130MPa have been studied. The results showed that with the increase of Ru content, the γ/γ eutectic volume fraction and the dendrite arm spacing decreased gradually. The γ' phase mean size in three alloys decreased with the increase of the Ru content. On the other hand, the dendrite segregation of Al, Ta towards interdendrite area and ReW towards dendrite core area was alleviated gradually with the increase of the Ru content. The increase of Ru content from 0 wt.% to 5 wt.% pronouncedly enhanced the stress rupture properties by suppressing the precipitation of TCP phases effectively at high temperature.

The Influence of Carbon Addition on Microstructure and Mechanical Properties of Fe-22.0Al-5.0Ti Alloy

2014 ◽  
Vol 1043 ◽  
pp. 17-21 ◽  
Author(s):  
Ravi Kant ◽  
Ashish Selokar ◽  
Vijaya Agarwala ◽  
U. Prakash
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
High Hardness ◽  
Low Carbon ◽  
Carbon Addition ◽  
Two Phase ◽  
Solid Solution Strengthening ◽  
Load Carrying ◽  
Solution Strengthening

The effect of carbon addition on Fe-22.0Al-5.0Ti alloy on structure and properties has been investigated. Microstructural and phase analysis have been investigated by using optical microscopy, scanning electron microscope (SEM) equipped with EDAX. For low carbon addition (0.1 wt.%), two-phase microstructure consisting of precipitates of TiC in B2 matrix. The presence of large amount of carbon (1.0 or 1.5 wt.%) resulted formation of Fe3AlC0.5 and TiC precipitates in B2 matrix. The results show that the mechanical properties of Fe-22.0Al-5.0Ti increased with increase in the carbon content and strongly depend upon nature and volume fraction of different precipitates. The volume fraction of precipitates increased with increase in the content of carbon. The behavior of Fe-22.0Al-5.0Ti alloy was explained by the combined effect of precipitation hardening and solid solution strengthening. The main effect of addition of carbon related to improvement in the compressive strength without loss in the ductility. The decrease in the wear rate is mainly attributed to the high hardness of the composites and as well hard TiC play a role of load carrying.

Sign in / Sign up

Export Citation Format

Share Document