Microstructure Control of Nb-Si Based Alloys with Cr, W, Ta and Zr by Using Nb3Si Phase Stability Control

ABSTRACTRecently, Nb-Si based alloys have attracted considerable attention as potential candidate materials for ultra-high temperature applications, because of their low densities and high melting points. However, it is still very difficult to obtain materials with a good balance of high-temperature strength and room-temperature toughness. To address this issue, microstructure control is considered to be a promising method. In applying microstructure control to Nb-Si based alloys with a eutectic reaction (L → Nbss + Nb3Si) and a eutectoid reaction (Nb3Si → Nbss + Nb5Si3), the key is the control of Nb3Si phase stability. Nbss (Nb solid solution) is considered as a ductile phase. In previous reports, it was revealed that different elements had different effects on the stability of Nb3Si. In particular, Mo and W (>3 at %) destabilize the Nb3Si phase, while Ti and Ta stabilize it, and Zr acts as an accelerator for decomposition of Nb3Si. On the other hand, Cr is known to enhance the formation of the ductile Nbss phase. In the present study, we investigated the effects of adding combinations of stabilizing, destabilizing, and accelerating elements with Cr, such as Cr and W, Cr and Ta, Cr and Zr. According to SEM observation, different microstructures were obtained with different combination of additives, and the fracture toughness at room temperature of these samples were also evaluated to reveal the effects of the microstructure on the mechanical properties of Nb-Si based alloys.

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Research on Effect of Alloy Elements on Equilibrium and Properties of Ni-Cr-Co Type Nickel-Based Superalloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.849.513 ◽

2016 ◽

Vol 849 ◽

pp. 513-519

Author(s):

Qing Quan Zhang ◽

Ming Yang Li ◽

Ran Wei ◽

Hui Yun Wu ◽

Zhen Rui Li

Keyword(s):

High Temperature ◽

Room Temperature ◽

High Temperature Strength ◽

Nickel Based Superalloy ◽

Type 3 ◽

Room Temperature Strength ◽

Super Alloy ◽

Type Nickel

Ni-Cr-Co type Nickel-based super alloy Inconel 740H was studied. The effect of Nb, Al and Ti on the equilibrium of this alloy was analyzed by JMatPro software. The amount of Ti and Nb should be controlled by 1.50wt.%, and meanwhile, Al should be 1.0-2.0wt.%. If Mo and W were added the amount of Mo should be in the range of 1.0-2.0wt. %, and W should be about 1.0wt.%. Based on these results, three types of new alloys were designed, which contain Ni-Cr-Co-Mo type (1#), Ni-Cr-Co-W type (2#) and Ni-Cr-Co-Mo-W type (3#). Compared with the Ni-Cr-Co type Inconel 740H alloy, the room temperature strength, high temperature strength and high temperature durable performance of the three new alloys improved, which can provide the evidence and reference to optimize the chemical composition of Inconel 740H alloy, i.e., adding 1.50wt.% Mo and 1.0wt.% W individually or together.

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Effect of Rolling Parameters on the Properties of Al-Fe-V Sheet Rolled on an Experimental Mill

MRS Proceedings ◽

10.1557/proc-58-285 ◽

1985 ◽

Vol 58 ◽

Cited By ~ 1

Author(s):

A. Brown ◽

D. Raybould

Keyword(s):

Fracture Toughness ◽

Corrosion Resistance ◽

High Temperature ◽

Aluminum Alloys ◽

Room Temperature ◽

Thermomechanical Processing ◽

High Temperature Strength ◽

Rapidly Solidified ◽

Large Sheet ◽

Room Temperature Strength

ABSTRACTIn recent years, interest in high temperature aluminum alloys has increased. However, nearly all the data available is for simple extrusions. This paper looks at the properties of sheet made from a rapidly solidified Al-10Fe-2.5V-2Si alloy. The sheet is made by direct forging followed by hot rolling, this is readily scalable, so allowing the production of large sheet. The room temperature strength and fracture toughness of the sheet are comparable to those of 2014-T6. The high temperature strength, specific stiffness and corrosion resistance are excellent. Recently, improved thermomechanical processing and new alloys have allowed higher strengths and fracture toughness values to be obtained.

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Microstructures and High-temperature Strength of Silicide-reinforced Nb Alloys

MRS Proceedings ◽

10.1557/proc-646-n5.39.1 ◽

2000 ◽

Vol 646 ◽

Cited By ~ 2

Author(s):

C.L. Ma ◽

Y. Tan ◽

H. Tanaka ◽

A. Kasama ◽

R. Tanaka ◽

...

Keyword(s):

High Temperature ◽

Quaternary System ◽

Eutectic Reaction ◽

High Temperature Strength ◽

Quaternary Alloys ◽

Two Phase ◽

Practical Applications ◽

Arc Melting ◽

Heat Treated ◽

Very High

ABSTRACTThis article describes the phase stability, microstructures and mechanical properties of silicide-reinforced Nb alloys in Nb-Mo-W-Si quaternary system prepared by arc melting and heat treatment. There exists an equilibrium two-phase field of Nb solid solution (Nbss) and α(Nb,Mo,W)5Si3 in a Nb-rich region of this quaternary system. Alloys in this region have a eutectic reaction of L → Nbss+β(Nb,Mo,W)5Si3 during solidification. The β(Nb,Mo,W)5Si3 transforms to the stable α(Nb,Mo,W)5Si3 at very high temperature. The cast and heat treated hypoeutectic alloys consist of dendritic Nbss, network-shaped Nbss matrix and α(Nb,Mo,W)5Si3. These quaternary alloys exhibit excellent high-temperature strength, although the fracture toughness is still unacceptable for practical applications.

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High Temperature Performance of Spark Plasma Sintered W0.5(TaTiVCr)0.5 Alloy

Metals ◽

10.3390/met10111512 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1512 ◽

Cited By ~ 2

Author(s):

Sajid Alvi ◽

Owais Ahmed Waseem ◽

Farid Akhtar

Keyword(s):

Wear Resistance ◽

Compressive Strength ◽

High Temperature ◽

Phase Stability ◽

Tungsten Alloy ◽

Compressive Yield Strength ◽

High Temperature Strength ◽

Secondary Phases ◽

High Temperature Xrd ◽

Spark Plasma

The phase stability, compressive strength, and tribology of tungsten alloy containing low activation elements, W0.5(TaTiVCr)0.5, at elevated temperature up to 1400 °C were investigated. The spark plasma sintered W0.5(TaTiVCr)0.5 alloy showed body centered cubic (BCC) structure, which was stable up to 1400 °C using in-situ high temperature XRD analysis and did not show formation of secondary phases. The W0.5(TaTiVCr)0.5 alloy showed exceptionally high compressive yield strength of 1136 ± 40 MPa, 830 ± 60 MPa and 425 ± 15 MPa at 1000 °C, 1200 °C and 1400 °C, respectively. The high temperature tribology at 400 °C showed an average coefficient of friction (COF) and low wear rate of 0.55 and 1.37 × 10−5 mm3/Nm, respectively. The superior compressive strength and wear resistance properties were attributed to the solid solution strengthening of the alloy. The low activation composition, high phase stability, superior high temperature strength, and good wear resistance at 400 °C of W0.5(TaTiVCr)0.5 suggest its potential utilization in extreme applications such as plasma facing materials, rocket nozzles and industrial tooling.

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Influence of Al-Cu-Mn-Fe-Ti Alloy Composition and Production Parameters of Extruded Semi-Finished Products on their Structure and Mechanical Properties

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.265.456 ◽

2017 ◽

Vol 265 ◽

pp. 456-462 ◽

Cited By ~ 1

Author(s):

P.L. Reznik ◽

Mikhail Lobanov

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Thermal Treatment ◽

Low Temperature ◽

Room Temperature ◽

High Temperature Strength ◽

Ti Alloy ◽

Low Temperature Annealing ◽

Annealing Conditions ◽

Concentration Changes

Studies have been conducted as to the effect of Cu, Mn, Fe concentration changes in Al-Cu-Mn-Fe-Ti alloy, the conditions of thermal and deformational treatment of ingots and extruded rods 40 mm in diameter on the microstructure, phase composition and mechanical properties. It has been determined that changing Al-6.3Cu-0.3Mn-0.17Fe-0.15Ti alloy to Al-6.5Cu-0.7Mn-0.11Fe-0.15Ti causes an increase in the strength characteristics of extruded rods at the room temperature both after molding and in tempered and aged conditions, irrespective of the conditions of thermal treatment of the initial ingot (low-temperature annealing 420 °С for 2 h, or high-temperature annealing at 530 °С for 12 h). Increasing the extruding temperature from 330 to 480 °С, along with increasing Cu, Mn and decreasing Fe in the alloy Al-Cu-Mn-Ti, is accompanied by the increased level of ultimate strength in a quenched condition by 25% to 410 MPa, irrespective of the annealing conditions of the original ingot. An opportunity to apply the Al-6.3Cu-0.3Mn-0.17Fe-0.15Ti alloy with low-temperature annealing at 420 °С for 2 h and the molding temperature of 330 °С has been found to produce rods where, in the condition of full thermal treatment (tempering at 535 °С + aging at 200 °С for 8 hours), a structure is formed that ensures satisfactory characteristics of high temperature strength by resisting to fracture for more than 100 hours at 300 °С and 70 MPa.

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Deformation of an extruded nickel beryllide between room temperature and 820 °C

Journal of Materials Research ◽

10.1557/jmr.1991.2653 ◽

1991 ◽

Vol 6 (12) ◽

pp. 2653-2659 ◽

Cited By ~ 2

Author(s):

G.M. Pharr ◽

S.V. Courington ◽

J. Wadsworth ◽

T.G. Nieh

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Elevated Temperature ◽

Flow Stress ◽

Strain Hardening ◽

Room Temperature ◽

High Temperature Strength ◽

Compression Tests ◽

Tension And Compression ◽

Better Than

The mechanical properties of nickel beryllide, NiBe, have been investigated in the temperature range 20–820 °C. The room temperature properties were studied using tension, bending, and compression tests, while the elevated temperature properties were characterized in compression only. NiBe exhibits some ductility at room temperature; the strains to failure in tension and compression are 1.3% and 13%, respectively. Fracture is controlled primarily by the cohesive strength of grain boundaries. At high temperatures, NiBe is readily deformable—strains in excess of 30% can be achieved at temperatures as low as 400 °C. Strain hardening rates are high, and the flow stress decreases monotonically with temperature. The high temperature strength of NiBe is as good or better than that of NiAl, but not quite as good as CoAl.

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Tough, Ductile High-Temperature Intermetallic Compounds: Results of a Four-Year Survey.

MRS Proceedings ◽

10.1557/proc-213-463 ◽

1990 ◽

Vol 213 ◽

Cited By ~ 10

Author(s):

R.L. Fleischer ◽

C.L. Briant ◽

R.D. Field

Keyword(s):

High Temperature ◽

Intermetallic Compounds ◽

Room Temperature ◽

Impact Resistance ◽

High Strength ◽

Aircraft Engine ◽

High Temperature Strength ◽

Beneficial Effects ◽

Strength And Stiffness ◽

Binary Compounds

ABSTRACTA four-year survey of high-temperature intermetallic compounds has been aimed at identifying potentially useful structural materials for aerospace and aircraft engine applications. Since the good properties of high strength and stiffness at high temperatures are typically negated by brittleness at ambient temperature, new materials must have roomtemperature toughness or ductility. Screening has been done of 90 binary compounds with 20 different crystal structures, and 130 ternary or higher-order alloys. Testing typically included hardness vs. temperature, elastic modulus determination, and toughness evaluation via a room-temperature chisel test. Four alloy systems, including only two types that are of the simplest structures, showed substantial room-temperature toughness: Al-Ru, Ru-Sc, Ir-Nb, and Ru-Ta. Of these the last and the first are the most promising. Special features of the Ru- Ta (L1o) alloys are their room-temperature impact resistance and high-temperature strength. AIRu (B2) alloys can be tougher than the L1o structures and most are also ductile in compression at room temperature. Alloying experiments with B, Cr, and Sc show beneficial effects on ductility, oxidation resistance, and high-temperature strength.

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