Rapidly Solidified Ti Alloys Containing Metalloids and Rare Earth Metals— Their Microstructure and Mechanical Properties

1983 ◽  
Vol 28 ◽  
Author(s):  
C.S. Chi ◽  
S.H. Whang
Keyword(s):  
Rare Earth ◽  
Melt Spinning ◽  
Elevated Temperatures ◽  
Age Hardening ◽  
Second Phase ◽  
Precipitation Reaction ◽  
Strength Increase ◽  
Ti Alloys ◽  
Significant Difference ◽  
Rapidly Solidified

ABSTRACTRapidly solidified (RS) Ti alloys containing novel additives were prepared by splat quenching and melt spinning techniques. Microstructures of the as-quenched and heat-treated alloys were studied by electron microscopies. The results show that microstructural refinement and precipitation reaction are universal phenomena in all RS Ti alloys. A significant difference in second phase coarsening was observed between metalloid-origin precipitates and those of rare earth-origin. The precipitates in a Ti-Al-La(Ce) were identified predominantly as rare earth-Al compounds. Exce llent stability for rare earth-origin precipitates was found.Except for a carbon-containing alloy (700 ° C), age hardening behavior is a universal phenomenon in all RS Ti alloys with additives. A significant strength increase (hardness) in the RS alloy was noted at both room and elevated temperatures.

Oxide Dispersions in Rapidly Solidified Ti Alloys

1983 ◽  
Vol 28 ◽  
Author(s):  
D.G. Konitzer ◽  
R. Kirchheim ◽  
H.L. Fraser
Keyword(s):  
Heat Treatment ◽  
Rare Earth ◽  
Rare Earth Oxide ◽  
Rapid Solidification Processing ◽  
Laser Surface ◽  
Second Phase ◽  
Solidification Processing ◽  
Ti Alloys ◽  
The Stability ◽  
Rapidly Solidified

ABSTRACTTechniques of rapid solidification processing were used to refine a dispersion of rare earth oxides in Ti. The dispersion was produced by laser surface melting and subsequent heat treatment of a Ti-Er alloy. The second phase was identified as the rare earth oxide. The stability of the dispersion was investigated analytically and experimentally and the correlation between the analysis and experiments was shown to be very good.

Grain-Coarsening Resistance and The Stability of Second-Phase Dispersions in Rapidly Solidified Steels

1981 ◽  
Vol 8 ◽  
Author(s):  
G. B. Olson ◽  
H. C. Ling ◽  
J. S. Montgomery ◽  
J. B. Vander Sande ◽  
M. Cohen
Keyword(s):  
Rare Earth ◽  
Grain Boundary ◽  
Alloy Composition ◽  
Second Phase ◽  
Alloy Development ◽  
Grain Coarsening ◽  
Dispersed Phases ◽  
Grain Boundary Pinning ◽  
The Stability ◽  
Rapidly Solidified

ABSTRACTControl of alloy composition and processing to achieve grain coarsening resistance in rapidly solidified alloys is examined via the theory of grain boundary pinning and particle coarsening. The principles are illustrated for the case of manganese sulfides in steels. A thermodynamic survey of potential stable dispersed phases identifies TiN and rare-earth sulfides as particularly promising for alloy development via rapid solidification.

Substructure Development in Rapidly Solidified B2-Type TiCo Ribbons

2005 ◽  
Vol 475-479 ◽  
pp. 849-852 ◽  
Author(s):  
Kyosuke Yoshimi ◽  
Minseok Sung ◽  
Sadahiro Tsurekawa ◽  
Akira Yamauchi ◽  
Ryusuke Nakamura ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Dislocation Density ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
Grain Structure ◽  
Second Phase ◽  
Rapidly Solidified ◽  
Equiaxed Grain

Substructure development through aging and annealing treatments was studied for rapidly solidified TiCo ribbons using TEM. In as-spun ribbons, equiaxed grain structure was developed and its crystal structure was B2-ordered immediately after melt-spinning, while a small amount of fine precipitates existed as second phase. Some grains were dislocation-free but others contained a certain amount of curved or helical dislocations and loops. The dislocation density in the ribbons annealed at 700 °C for 24 h was obviously higher than those in the as-spun ribbons and the ribbons aged at 200 °C for 100 h. The increase of the dislocation density in the annealed ribbons would result from the absorption of excess vacancies. Therefore, the obtained results indicated that a large amount of supersaturated thermal vacancies were retained in TiCo as-spun ribbons by the rapid solidification.

Microstructures Development in Al-5Fe and Al-5Fe-3Y Alloys Solidified at Different Cooling Rate

2011 ◽  
Vol 189-193 ◽  
pp. 2462-2466
Author(s):  
Guo Fa Mi ◽  
Cui Fen Dong ◽  
Chang Yun Li ◽  
Hai Yan Wang
Keyword(s):  
Rare Earth ◽  
Phase Composition ◽  
Intermetallic Compound ◽  
Cooling Rate ◽  
Melt Spinning ◽  
Metastable Phase ◽  
Vacuum Melting ◽  
Suction Casting ◽  
Rapidly Solidified

Cast, sub-rapidly solidified and rapidly solidified Al-5Fe alloy and Al-5Fe-3Y alloy were respectively prepared by vacuum melting, suction casting and melt spinning. The effect of increasing cooling rate and adding rare earth Y alloy on microstructures and phase composition were investigated. The results showed that the acicular Al3Fe phase transferred to spherical phase and dispersed secondary precipitations were also found when 3.0 wt% Y was added in the Al-5Fe alloy. Meanwhile, the microstructures were apparently refined by the increasing of cooling rate. The metastable phase A16Fe and intermetallic compound A110Fe2Y phase have been observed in Al-5Fe alloy and Al-5Fe-3Y alloy, respectively.

Effect of Mg Addition on the Mechanical Properties of Rapidly Solidified Al-Mn Alloys at Elevated Temperatures

2010 ◽  
Vol 638-642 ◽  
pp. 339-344
Author(s):  
Makoto Sugamata ◽  
Akio Tomioka ◽  
Yousuke Kubota
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Tensile Strength ◽  
Intermetallic Compounds ◽  
Elevated Temperatures ◽  
Optical Microscope ◽  
Strength Increase ◽  
Positive Effects ◽  
Uniform Dispersion ◽  
Rapidly Solidified

With an aim of clarifying the strength of rapidly solidified P/M materials strengthened by solid solution of Mg and dispersion of transition metal compounds at elevated temperature, Al-2mass%Mn, Al-4mass%Mn and Al-6mass%Mn alloys with varied Mg additions of 0, 1 and 3 mass% were prepared by rapid solidification techniques. Rapidly solidified (RS) flakes were produced by remelting alloy ingots in a graphite crucible, atomizing the alloy melt and subsequent splat-quenching on a rotating water-cooled copper roll under argon atmosphere.　The RS flakes were consolidated to the P/M materials by hot extrusion after vacuum degassing. Cast ingots of these alloys were also hot-extruded under the same conditions to the I/M as reference materials. Metallographic structures and constituent phases were studied for the P/M and I/M materials by optical microscope and X-ray diffraction. Mechanical properties of as-extruded and annealed P/M materials and as-extruded I/M materials were examined by tensile test at room and elevated temperatures under various strain rates. Uniform dispersion of fine intermetallic compounds (Al6Mn) was observed in all the as-extruded P/M materials. Added Mg was present as the solute in I/M and P/M materials alloy even after annealing. The P/M materials containing Mg exhibited higher hardness and strength at room temperature, than those without Mg. It was considered that both solid solution of Mg and dispersion of intermetallic compounds were contributing the hardness and strength increase in the rapidly solidified Al-Mn-Mg alloys. Tensile strength increases with increasing amount of Mg in I/M materials at all testing temperatures. However, strength of as-extruded P/M materials decreases with addition of Mg at 573K and 673K. Thus the positive effects of Mg additions on tensile strength of as-extruded P/M materials disappeared at higher testing temperature. Tensile strength of annealed P/M materials in which dislocation density decreased and compound particle coarsened increased with addition of Mg at elevated temperatures.

Rapidly solidified Al3Ti-base alloys containing Ni

1988 ◽  
Vol 3 (1) ◽  
pp. 1-7 ◽  
Author(s):  
S. C. Huang ◽  
E. L. Hall ◽  
M. F. X. Gigliotti
Keyword(s):  
Melt Spinning ◽  
Single Phase ◽  
Analytical Electron Microscopy ◽  
Primary Phase ◽  
Second Phase ◽  
Equilibrium Conditions ◽  
Second Phase Particles ◽  
Analytical Electron ◽  
Wheel Side ◽  
Rapidly Solidified

Two Ni-modified Al3Ti alloys (Al65Ni10Ti25 and Al62Ni8Ti30) were rapidly solidified by melt spinning. The resulting microstructure was studied using light microscopy and analytical electron microscopy. Significant variations in the microstructure and phases were observed between the two ribbons and through the thickness of each ribbon.A single-phase γ-TiAl structure was seen near the wheel side of the Al62Ni8Ti30 ribbon, having microcrystalline grains ∼ 100 nm in diameter. Second-phase particles of Λ-AlNiTi were found in the remaining regions of that ribbon as the structure became columnar due to reduced rates of cooling. The Al65Ni10Ti25 alloy exhibited a primary phase of π-Al6.5 NiTi2.5. A second phase of μ-Al2NiTi formed with morphology and distribution varying through thickness. Microchemistry measurements on the phases indicated substantial deviations (up to 14 at. %) from the stoichiometric compositions. Further, the π, γ, and μ are low-temperature phases that do not form by solidification under equilibrium conditions. The observation of these phases thus suggests significant undercoolings achieved during the melt-spinning processing of the present alloys. Both ribbons are brittle as spun.

Dispersoid Modification of Ti3Al-Nb Alloys

1985 ◽  
Vol 58 ◽  
Author(s):  
R. G. Rowe ◽  
J. A. Sutliff ◽  
E. F. Koch
Keyword(s):  
Fracture Toughness ◽  
Rare Earth ◽  
Titanium Aluminide ◽  
Melt Spinning ◽  
Room Temperature ◽  
Beta Transus ◽  
Processing Conditions ◽  
Room Temperature Ductility ◽  
Rapidly Solidified ◽  
Titanium Aluminide Alloys

ABSTRACTTitanium aluminide alloys with matrix compositions of essentially Ti3Al plus 0, 5, 7.5, and 10 a/o Nb and with and without rare earth elements for dispersoid formation were prepared. The alloys were rapidly solidified by melt spinning. Ribbon was consolidated by HIP and extrusion at temperatures below the beta transus temperatures of the alloys. The effects of processing conditions and dispersoid additions on room temperature ductility and fracture toughness were studied.

Effect of Different Cooling Speed and Rare Earth La on the Microstructures and Phase Constitution of Al-Fe Alloy

2010 ◽  
Vol 44-47 ◽  
pp. 2126-2130 ◽  
Author(s):  
Guo Fa Mi ◽  
Cui Fen Dong ◽  
Da Wei Zhao
Keyword(s):  
Rare Earth ◽  
Melt Spinning ◽  
Metastable Phase ◽  
Melting Furnace ◽  
High Melting Point ◽  
The Matrix ◽  
Cooling Speed ◽  
Matrix Morphology ◽  
Rapidly Solidified ◽  
Rare Earth La

The casting, sub-rapid solidified and rapidly solidified A1-5Fe alloys, with or without rare earth La have been respectively prepared by vacuum melting furnace, suction casting and melt spinning furnace. And the alloys were investigated with OM, TEM and XRD. The results show that the microstructure was apparently refined by the increasing of cooling rate. Meanwhile, the acicular Al3Fe phase transferred to flower-like phase in casting A1-5Fe alloy and the matrix morphology of the alloy also was changed in sub-rapidly solidified Al-5Fe alloy, while 1.5wt% La was added. The metastable phase A16Fe and Al11La3 phase with high melting point were found in Al-5Fe alloy and A1-5Fe-1.5La alloy.

Rapidly solidified Al-Ti alloys via advanced melt spinning

JOM ◽  
1989 ◽  
Vol 41 (5) ◽  
pp. 27-30 ◽  
Author(s):  
S. C. Jha ◽  
T. A. Mozhi ◽  
R. Ray
Keyword(s):  
Melt Spinning ◽  
Ti Alloys ◽  
Rapidly Solidified

Rare Earth Oxide Dispersoid Stability and Microstructural Effects in Rapidly Solidified Ti3Al and Ti3A1-Nb

1985 ◽  
Vol 58 ◽  
Author(s):  
J. A. Sutliff ◽  
R. G. Rowe
Keyword(s):  
Rare Earth ◽  
Titanium Aluminide ◽  
Melt Spinning ◽  
Analytical Electron Microscopy ◽  
Rare Earth Oxide ◽  
Microstructural Effects ◽  
Analytical Electron ◽  
The Matrix ◽  
Rapidly Solidified ◽  
Titanium Aluminide Alloys

ABSTRACTThe microstructures of titanium aluminide alloys containing a rare earth oxide dispersion have been characterized using analytical electron microscopy. The alloys, based on Ti3A1 (alpha-2), contained 0 to 10.7 atom% Nb and 0.5 atom% Er. Alloys were rapidly solidified by melt spinning and were subsequently consolidated by HIP and extrusion. The microstructure of each alloy was examined in the as-cast, as-HIP'ed, and as-extruded conditions. A fine dispersoid spaced less than 100 nm apart was observed in ribbon aged at 750°C. The effects of processing conditions on the dispersoid distribution as a function of matrix chemistry were studied. Hot deformation was also examined to investigate the nature of the interaction between the dispersoids and the matrix during deformation.

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