Deformation Behavior of High Temperature Intermetallic TiAl Alloyed with Gallium

1988 ◽  
Vol 133 ◽  
Author(s):  
B. Kad ◽  
B. F. Oliver
Keyword(s):  
High Temperature ◽  
Optical Microscopy ◽  
Deformation Behavior ◽  
Single Phase ◽  
Single Phase Alloy ◽  
Microhardness Data ◽  
Ternary Additions ◽  
Wavy Slip

ABSTRACTTiAl (γ) intermetallic has been investigated with ternary additions of up to 10 at% Ga. Optical microscopy reveals that gallium can be retained in solution to at least 7 at%. Microhardness data reveals that Ga substituted for Al such that Ti/(Al+Ga)=l causes solution softening. Deformation behavior of the single phase alloy in compression is reported. Perfect dislocations of the a/2[110] type and superdislocations of the a[011] type and a/2[112] type have been observed. TEM results indicate that primary deformation is contributed by a/2[110] type dislocations and twinning on (111) planes with wavy slip optically observed

Constitutive Analysis of the High-Temperature Deformation Behavior of Single Phase α-Ti and α+β Ti-6Al-4V Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 3607-3612 ◽  
Author(s):  
Jeoung Han Kim ◽  
Jong Taek Yeom ◽  
Nho Kwang Park ◽  
Chong Soo Lee
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Deformation Behavior ◽  
Single Phase ◽  
Volume Fraction ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Β Phase ◽  
Α Phase ◽  
Self Consistent

The high-temperature deformation behavior of the single-phase α (Ti-7.0Al-1.5V) and α + β (Ti-6Al-4V) alloy were determined and compared within the framework of self-consistent scheme at various temperature ranges. For this purpose, isothermal hot compression tests were conducted at temperatures between 650°C ~ 950°C to determine the effect of α/β phase volume fraction on average flow stress under hot-working condition. The flow behavior of α phase was estimated from the compression test results of single-phase α alloy whose chemical composition is close to that of α phase of Ti-6Al-4V alloy. On the other hand, the flow stress of β phase in Ti-6Al-4V was predicted by using self-consistent method. The flow stress of α phase was higher than that of β phase above 750°C, while the β phase revealed higher flow stress than α phase at 650°C. Also, at temperature above 750°C, the predicted strain rate of β phase was higher than that of α phase. It was found that the relative strength between α and β phase significantly varied with temperature.

Ductility and Strength in Mo Modified TiAl

1990 ◽  
Vol 213 ◽  
Author(s):  
T. Maeda ◽  
M. Okada ◽  
Y. Shida
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Single Phase ◽  
Tensile Ductility ◽  
Rupture Strength ◽  
High Temperature Strength ◽  
Duplex Structure ◽  
Annealed Condition ◽  
Mean Grain Size ◽  
Ternary Additions

ABSTRACTAn investigation has been made on the effect of ternary additions of Mo and other elements on the room temperature tensile ductility and high temperature strength, including creep rupture strength in TiAl based alloys. Mo modified Ti-rich TiAl in an annealed condition exhibited higher tensile ductility at room temperature than other well-known Cr or Mn modified alloys, this resulting from the refinment of mean grain size in the duplex structure of lamellar (γ+α2) and single phase (γ) rather than the crystalline tetragonality of the γ phase. Moreover, creep strength in as cast Ti-rich TiAl is improved with the addition of Mo, and lowered with the addition of Mn. These results suggest that Mo modified Ti-rich TiAl can enhance, the potential of TiAl as a high temperature material more than other ternary modified TiAl.

Superplastic Deformation Behavior of Zn-Al Alloys

1999 ◽  
Vol 601 ◽  
Author(s):  
Tae Kwon Ha ◽  
Hyun Woo Koo ◽  
Tae Shin Eom ◽  
Young Won Chang
Keyword(s):  
Deformation Behavior ◽  
Superplastic Deformation ◽  
Room Temperature ◽  
Single Phase ◽  
Internal Variable ◽  
Al Alloys ◽  
Load Relaxation ◽  
Variable Theory ◽  
Single Phase Alloy ◽  
Internal Variable Theory

AbstractThe superplastic deformation behavior of a quasi-single phase Zn-0.3 wt.% Al and a microduplex Zn-22 wt.% Al eutectoid alloy has been investigated in this study within the framework of the internal variable theory of structural superplasticity (SSP). Load relaxation and tensile tests were conducted at room temperature for quasi-single phase alloy and at 200°C for eutectoid alloy. The flow curves obtained from load relaxation tests on superplastic Zn-Al alloys were shown to consist of the contributions from interface sliding (IS) and the accommodating plastic deformation due to dislocation activities. The IS behavior could be described as a viscous flow characterized by the power index value of Mg = 0.5. In the case of quasi-single phase Zn-0.3 wt.% Al alloy with the average grain size of 1 µm, a large elongation of about 1400 % was obtained at room temperature. In a relatively large-grained (10 µm) single-phase alloy, however, grain boundary sliding (GBS) was not expected from the analysis based on the internal variable theory of SSP.

Study of as-cast Nb-Ru samples

MRS Advances ◽  
2018 ◽  
Vol 3 (34-35) ◽  
pp. 1949-1953
Author(s):  
S. Samal ◽  
L.A. Cornish
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Shape Memory ◽  
Optical Microscopy ◽  
Solid Solutions ◽  
Single Phase ◽  
Intermetallic Phases ◽  
Argon Atmosphere ◽  
Arc Melting ◽  
Cast Alloys

AbstractThe Nb-Ru system is of interest because the ∼NbRu phase has potential for high temperature shape memory alloys. Previous workers have identified the phase transformation variously as involving twinning, of cubic-to-tetragonal and tetragonal–to-orthorhombic (or monoclinic) transformations. As well as the terminal (Nb) and (Ru) solid solutions, two intermetallic phases have been identified: ∼NbRu and ∼NbRu3 / ∼Nb3Ru5 / ∼NbRu2, but the boundaries between the different phases are still not fully established. This investigation looked at six as-cast alloys of different compositions across the Nb-Ru system, which were made from 99.95 % purity Nb and Ru. The samples were made by arc-melting under an argon atmosphere, using titanium as an oxygen-getter. These samples were sectioned and prepared metallographically for optical microscopy, SEM and XRD analyses, the latter using an X’pert database. The phases found were (Nb), (Ru), ∼NbRu and “∼NbRu3”, as expected. Although the samples were mainly homogeneous, there was porosity in the (Ru) phase between the “∼NbRu3” dendrites in the Nb28.5:Ru71.5 at.% sample. The Nb14.2:Ru85.8 at.% sample was mainly single-phase (Ru).

COPPER ALLOY No. 230

Alloy Digest ◽  
1972 ◽  
Vol 21 (3) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Shear Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Copper Alloy ◽  
Single Phase ◽  
Heat Treating ◽  
Temperature Performance

Abstract COPPER ALLOY No. 230 is a single-phase brass containing 15% zinc which is the most widely used of the low zinc brasses. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness and creep. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-252. Producer or source: Brass mills.

scholarly journals Fabrication and Characterization of Quinary High Entropy-Ultra-High Temperature Diborides

Ceramics ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 108-120
Author(s):  
Simone Barbarossa ◽  
Roberto Orrù ◽  
Valeria Cannillo ◽  
Antonio Iacomini ◽  
Sebastiano Garroni ◽  
...  
Keyword(s):  
High Temperature ◽  
Single Phase ◽  
Nominal Composition ◽  
High Entropy ◽  
Chemical Complexity ◽  
Alternative Processing ◽  
Plasma Sintering ◽  
High Temperature Synthesis ◽  
Spark Plasma

Due to their inherent chemical complexity and their refractory nature, the obtainment of highly dense and single-phase high entropy (HE) diborides represents a very hard target to achieve. In this framework, homogeneous (Hf0.2Nb0.2Ta0.2Mo0.2Ti0.2)B2, (Hf0.2Zr0.2Ta0.2Mo0.2Ti0.2)B2, and (Hf0.2Zr0.2Nb0.2Mo0.2Ti0.2)B2 ceramics with high relative densities (97.4, 96.5, and 98.2%, respectively) were successfully produced by spark plasma sintering (SPS) using powders prepared by self-propagating high-temperature synthesis (SHS). Although the latter technique did not lead to the complete conversion of initial precursors into the prescribed HE phases, such a goal was fully reached after SPS (1950 °C/20 min/20 MPa). The three HE products showed similar and, in some cases, even better mechanical properties compared to ceramics with the same nominal composition attained using alternative processing methods. Superior Vickers hardness and elastic modulus values were found for the (Hf0.2Nb0.2Ta0.2Mo0.2Ti0.2)B2 and the (Hf0.2Zr0.2Ta0.2Mo0.2Ti0.2)B2 systems, i.e., 28.1 GPa/538.5 GPa and 28.08 GPa/498.1 GPa, respectively, in spite of the correspondingly higher residual porosities (1.2 and 2.2 vol.%, respectively). In contrast, the third ceramic, not containing tantalum, displayed lower values of these two properties (25.1 GPa/404.5 GPa). However, the corresponding fracture toughness (8.84 MPa m1/2) was relatively higher. This fact can be likely ascribed to the smaller residual porosity (0.3 vol.%) of the sintered material.

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