Microstructure of Titanium-Aluminides after Thermomechanical Treatment

1990 ◽  
Vol 213 ◽  
Author(s):  
J. Seeger ◽  
C. Hartig ◽  
A. Bartels ◽  
H. Mecking
Keyword(s):  
Heat Treatment ◽  
Dynamic Recrystallization ◽  
Thermomechanical Treatment ◽  
Phase Field ◽  
Room Temperature ◽  
Titanium Aluminides ◽  
Subsequent Heat Treatment ◽  
Grain Sizes ◽  
Room Temperature Ductility ◽  
Residual Amount

ABSTRACTForging in the α2+γ-phase field results in grain refined zones by dynamic recrystallization, but still coarse γ-grains and a residual amount of α2/γ-lamellae are observed. During subsequent heat treatment in the α+γ-phase field the recrystallization leads to inhomogeneous distributions of α2-Ti3Al and grain sizes of γ-TiAl. Due to these inhomogeneities a significant increase of the room temperature ductility is not found.

Effect of Trace Boron Addition on the Microstructure and Tensile Elongation of Ti2AlNb-Based Orthorhombic Titanium Alloys

2010 ◽  
Vol 638-642 ◽  
pp. 1439-1444
Author(s):  
Masuo Hagiwara ◽  
Tomoyuki Kitaura
Keyword(s):  
Grain Size ◽  
Room Temperature ◽  
Tensile Elongation ◽  
Boron Addition ◽  
Grain Sizes ◽  
Solution Treated Condition ◽  
Room Temperature Ductility ◽  
Solution Treated ◽  
Treated Condition ◽  
Orthorhombic Titanium

The grain sizes of two kinds of orthorhombic alloys, namely (O+B2) Ti-22Al-11Nb-2Mo -1Fe and (O+2) Ti-27.5Al-13Nb have been successfully reduced by the addition of trace boron (B) (less than 0.12 wt.%). For example, the grain size in the B2 solution-treated condition was reduced from 1 mm to 80 m by the addition of 0.05% B for both alloys. The tensile elongation of Ti-22Al-11Nb-2Mo-1Fe at room temperature and 650C was increased from 0.3% to 4.3%, and from 8.2% to 30.3%, respectively, by the addition of 0.10% B. Ti-27.5Al-13Nb also showed an improved room temperature ductility by the minor B addition.

scholarly journals Ferromagnetic-like behaviour in bismuth ferrite films prepared by electrodeposition and subsequent heat treatment

RSC Advances ◽  
2017 ◽  
Vol 7 (51) ◽  
pp. 32133-32138 ◽  
Author(s):  
Doga Bilican ◽  
Enric Menéndez ◽  
Jin Zhang ◽  
Pau Solsona ◽  
Jordina Fornell ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Room Temperature ◽  
Bismuth Ferrite ◽  
Subsequent Heat Treatment ◽  
Ferrite Films

BiFeO3 films are achieved by electrodeposition followed by heat-treatment in air. The films show ferromagnetic-like behaviour at room temperature.

scholarly journals Synthesis, Characterization and Mechanical Properties of Nanocrystalline NiAl

1996 ◽  
Vol 457 ◽  
Author(s):  
M. S. Choudry ◽  
J. A. Eastman ◽  
R. J. DiMelfi ◽  
M. Dollar
Keyword(s):  
Room Temperature ◽  
Dark Field ◽  
Inert Gas ◽  
Coarse Grained ◽  
Gas Condensation ◽  
Grain Sizes ◽  
Room Temperature Ductility ◽  
Cast Alloys ◽  
Bend Tests

ABSTRACTNanocrystalline NiAl has been produced from pre-cast alloys using an electron beam inert gas condensation system. In-situ compaction was carried out at 100 to 300°C under vacuum conditions. Energy dispersive spectroscopy was used to determine chemical composition and homogeneity. Average grain sizes in the range of 4 to 10 nm were found from TEM dark field analyses. A compression-cage fixture was designed to perform disk bend tests. These tests revealed substantial room temperature ductility in nanocrystalline NiAl, while coarse grained NiAl showed no measurable room temperature ductility.

Order Effect of Vacuum and Ammonia Atmospheres on Aluminium Nitriding by Mechanical Alloying

2012 ◽  
Vol 730-732 ◽  
pp. 936-941 ◽  
Author(s):  
Eduardo Sánchez Caballero ◽  
J. Cintas ◽  
M. Herrera-García ◽  
Francicso Gomez Cuevas ◽  
Juan M. Montes
Keyword(s):  
Heat Treatment ◽  
Mechanical Alloying ◽  
Room Temperature ◽  
Order Effect ◽  
Milling Process ◽  
Subsequent Heat Treatment ◽  
Aluminium Powder ◽  
Xrd Study ◽  
Aluminium Lattice

Aluminium powder was milled under vacuum and/or ammonia atmospheres, in order to evaluate the effect of the order of the atmospheres on the amount of nitrides appearing in the powder after a subsequent heat treatment. All milling experiences were carried out at room temperature for 5 h. The XRD study of sintered powders showed that important amounts of AlN appeared after heating. The use of vacuum and ammonia flow allows controlling the percentage of N rich phases formed. Moreover, the capacity of incorporating nitrogen to the aluminium lattice is very influenced by the vacuum and ammonia flow atmospheres order during the milling process.

Improvement of Creep Performance of Creep Strength Enhanced Ferritic (CSEF) Steel Weldments Through Non-Standard Heat Treatments

2014 ◽  
Author(s):  
Yukinori Yamamoto ◽  
Xinghua Yu ◽  
Sudarsanam Suresh Babu
Keyword(s):  
Heat Treatment ◽  
Base Metal ◽  
Room Temperature ◽  
Rupture Life ◽  
Creep Properties ◽  
Standard Heat ◽  
Fine Grained ◽  
Room Temperature Ductility ◽  
Grade 91 ◽  
Lower Temperature

Significant improvement of creep-rupture life was observed in Grade 91 (modified 9Cr-1Mo) steel weldments when a non-standard heat-treatment was applied prior to welding. A lower temperature pre-weld tempering (LTT) than the typical heat-treatment resulted in a complete dissolution of M23C6 carbides in the fine-grained heat affected zone (FGHAZ) during welding, which allowed re-precipitation of the M23C6 as strengthening carbides after post-weld heat treatment. However, the LTT also raised the ductile-brittle transition temperature of the base metal above room temperature. A thermo-mechanical treatment (TMT) has been proposed in the present study as a way of balancing the need for improved creep properties in the weld region and an acceptable level of room temperature ductility in the base metal. Aus-forging and subsequent aus-aging promotes MX formation prior to martensitic transformation which effectively increases the creep resistance, even in the FGHAZ. The application of the standard tempering after the TMT process improves the room temperature ductility without losing the advantage of improved strength. Preliminary results indicate a successful improvement of the cross-weld creep properties of the TMT sample similar to the LTT sample. Paper published with permission.

Annealing Effect on Microstructure and Coercivity of YCo5 Nanoparticles Obtained by Mechanical Milling

2009 ◽  
Vol 68 ◽  
pp. 122-126
Author(s):  
José Trinidad Elizalde Galindo ◽  
Reiko Sato Turtelli ◽  
Roland Grössinger ◽  
José Andrés Matutes-Aquino
Keyword(s):  
Heat Treatment ◽  
Exchange Interaction ◽  
Mechanical Milling ◽  
Room Temperature ◽  
Hysteresis Loops ◽  
Annealing Effect ◽  
Subsequent Heat Treatment ◽  
High Coercivity ◽  
Crystallite Sizes

Nanocrystalline YCo5 powders with high coercivity were prepared by mechanical milling and subsequent heat treatment at 820 °C for different annealing times, ta = 2.5, 3.0, 3.5 and 4.5 min, obtaining average crystallite sizes of <D>  17, 19, 32 and 39 nm., respectively. The coercivity values were determined from the hysteresis loops measured at maxima fields of Hm = 5 and 20 T. The highest coercivity was obtained for the sample exhibiting <D>  19 nm, where at room temperature and Hm = 5 T, the coercivity value is of 9.0 kOe. At 77 K and Hm = 5 T, the coercivity increase to 11.8 kOe and for Hm = 20 T, a higher value such as 13.1 kOe was found. The Ms/Mr ratio is enhanced to 0.62 indicating the occurrence of exchange interaction among nanocrystalline magnets.

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