scholarly journals Microstructure Control of Welded Joints of Dissimilar Titanium Alloys by Isothermal Forging

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3347
Author(s):  
Yongqiang Zhang ◽  
Xiangyi Xue ◽  
Jingli Zhang ◽  
Huiming Li ◽  
Ping Guo ◽  
...  
Keyword(s):  
Titanium Alloys ◽  
Welded Joints ◽  
Deformation Temperature ◽  
Temperature Deformation ◽  
Isothermal Forging ◽  
Deformation Parameters ◽  
Deformation Speed ◽  
Second Phases ◽  
Equiaxed Grains ◽  
Kinetics Of

In this study, the welded joints of dissimilar titanium alloys Ti600/Ti-22Al-25Nb were strengthened by isothermal forging. Different deformation parameters, including temperature, deformation speed, and reduction, were chosen. By isothermal forging, the original coarse dendritic grains of the welded joints were broken up effectively to form a large number of equiaxed grains. Meanwhile, many second phases were precipitated in the grain. Additionally, the dynamic globularization kinetics of second phases within the welded joints were quantitatively characterized and investigated. The results showed that the dynamic globularization kinetics and globularization rate were sensitive to the deformation conditions, and were promoted by a reduced strain rate and an elevated deformation temperature.

Improvement of hot forging process of П-shaped forgings from VT14 and VT23 alloys

2020 ◽  
pp. 502-507
Author(s):  
V.I. Galkin ◽  
P.A. Golovkin ◽  
S.A. Fesenko
Keyword(s):  
Titanium Alloys ◽  
Hot Forging ◽  
Effect Of Temperature ◽  
Temperature Deformation ◽  
Structure And Properties ◽  
Forging Process ◽  
Deformation Parameters ◽  
Hot Forging Process

The effect of temperature deformation parameters and the workpiece shape on the structure and properties of П-shaped die forgings made of the VT14 and VT23 titanium alloys.

Development of thermal rolling regimes of low-alloy “ARC”-steel with quasi-homogeneous ferrite-bainitic structure

2021 ◽  
pp. 7-20
Author(s):  
O. V. Sych ◽  
S. V. Korotovskaya ◽  
E. I. Khlusova ◽  
N. S. Novoskoltsev
Keyword(s):  
Thermal Deformation ◽  
Static Recrystallization ◽  
Temperature Deformation ◽  
Structure And Properties ◽  
Deformation Parameters ◽  
Bainitic Structure ◽  
Austenite Grains ◽  
Sheet Products ◽  
Deformation Modes ◽  
Kinetics Of

In this work, the kinetics of the growth of austenite grains upon heating, the features of the processes of dynamic and static recrystallization occurring at various temperature-deformation modes of plastic deformation are investigated. Phase transformations have been studied during continuous cooling of hotdeformed austenite in low-alloy “Arc”-steel with a yield point of at least 420 MPa. The studies carried out made it possible to determine the thermal deformation parameters that ensure the formation of a finely dispersed homogeneous ferrite-bainitic structure, on the basis of which technological recommendations for industrial production were developed and sheet products were manufactured. Presented are the structure and properties of sheet metal from shipbuilding “Arc”-strength category 420 MPa.

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

A Study of the Influence of Local Heat Treatment on the Structure of Welded Titanium Pipelines

2021 ◽  
Vol 410 ◽  
pp. 37-41
Author(s):  
Natalia A. Astafeva ◽  
Andrey A. Balanovskiy ◽  
Anna A. Pershina
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
Titanium Alloys ◽  
Welded Joints ◽  
Treatment Method ◽  
Local Heat ◽  
Optical Metallography ◽  
Heat Treated ◽  
Weld Structure ◽  
Heat Treatment Method

The article analyzes the results of a study of the influence of zonal heat treatment on the structure of welded joints of pipeline elements made of titanium alloys Ti-3.5Al-1.5Mn. In the manufacture of such structures, the TIG welding method is used to join pipe elements, after which the heat treatment method can be used to relieve residual stresses. The experiments have confirmed the effectiveness of zonal heat treatment preceded by welding. It was revealed that for welded joints made of titanium alloys, heat treatment can stabilize the structure. In experiments conducted by the method of optical metallography, the structure of heat treated and untreated welded joints was investigated. The influence of heat treatment on the weld structure and heat-affected zone was identified.

Microstructure of Nb3 (AlSiB) superconducting tapes with extremely high critical current densities

1989 ◽  
Vol 4 (3) ◽  
pp. 526-529 ◽  
Author(s):  
Mireille Treuil Clapp ◽  
Zhang Jian ◽  
Tariq Manzur
Keyword(s):  
Critical Current ◽  
Melt Spinning ◽  
Quenching Rate ◽  
Fine Grained ◽  
Annealing Conditions ◽  
Second Phases ◽  
Current Densities ◽  
Rapidly Solidified ◽  
Equiaxed Grains ◽  
A15 Phase

Alloys of Nb73Al12Si14.5B0.5 were rapidly solidified into amorphous ribbons using the melt spinning technique. These were isothermally annealed at temperatures ranging from 660 to 780 °C. The A15 phase began to crystallize at 700 °C and small amounts of second phases appeared at the higher temperatures. Crystallization was dependent on quenching rate as well as annealing conditions. Below 750 °C nucleation was nonuniform and was enhanced by surfaces and quenched-in nuclei. Above 750 °C nucleation became more uniform and completely crystalline ribbons with equiaxed grains ∼30 nm in diameter were obtained. These ultra fine grained ribbons had extremely high superconducting critical current densities of 8 × 1010 A/m2 and 5 × 1010 A/m2 at magnetic fields of 0.5 and 15 tesla, respectively, at 4.2 K.

Isothermal Forging of Precise Titanium Alloys Blanks for Medical Applications

1994 ◽  
Vol 170-172 ◽  
pp. 731-736 ◽  
Author(s):  
V.V. Boytsov ◽  
S.E. Goutman ◽  
Yu.V. Djuromsky ◽  
V.I. Maslennikova
Keyword(s):  
Titanium Alloys ◽  
Medical Applications ◽  
Isothermal Forging

Microstructure Evolution and Coarsening Mechanism of 7075 Semi-Solid Aluminum Alloy Pre-Deformed by ECAP Method

2016 ◽  
Vol 256 ◽  
pp. 294-300 ◽  
Author(s):  
Jin Long Fu ◽  
Yu Wei Wang ◽  
Kai Kun Wang ◽  
Xiao Wei Li
Keyword(s):  
Aluminum Alloy ◽  
Solid State ◽  
Ostwald Ripening ◽  
Liquid Fraction ◽  
Isothermal Holding ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Semi Solid ◽  
Equiaxed Grains ◽  
Kinetics Of

To investigate the influence of refined grains on the microstructure of 7075 aluminum alloy in semi-solid state, a new strain induced melting activation (SIMA) method was put forward containing two main stages: pre-deformation with equal channel angular pressing (ECAP) method and isothermally holding in the semi-solid temperature range. The breaking up and growth mechanisms of the grains and kinetics of equiaxed grains coarsening during the semi-solid holding were investigated. The results showed that the average grain size after ECAP extrusion decreased significantly, e.g., microstructure with average globular diameter less than 5μm was achieved after four-pass ECAP extrusion. Obvious grain coarsening had been found during isothermal holding in the semi-solid state and the roundness of the grains increased with the increasing holding time. The proper microstructure of 66.8μm in diameter and 1.22 in shape factor was obtained under proper soaking condition (at 590°C for 15 min). Two coarsening mechanisms, namely, coalescence in lower liquid fraction and Ostwald ripening in higher liquid fraction contributed to the grain growth process.

Efficiency of Microstructure Refinement in Ti-Based Alloys

2021 ◽  
Vol 1016 ◽  
pp. 1753-1758
Author(s):  
Sergey Zherebtsov ◽  
Nikita Stepanov ◽  
Gennady Salishchev
Keyword(s):  
Plastic Deformation ◽  
Chemical Composition ◽  
Titanium Alloys ◽  
Microstructure Evolution ◽  
Large Plastic Deformation ◽  
Two Phase ◽  
Microstructure Refinement ◽  
Kinetics Of ◽  
Rate Type ◽  
Lamellar Type

The influence of various factors on the efficiency of microstructure refinement in two-phase titanium alloys with respect to a well-known Ti-6Al-4V alloy was discussed. The kinetics of microstructure evolution in titanium alloys with a lamellar type α/β microstructure during large plastic deformation depends mainly on temperature and strain rate, type of the initial microstructure, thickness of the α lamellae, path of deformation and chemical composition. Each parameter should be controlled to provide the most efficient microstructure refinement during conventional metalforming methods.

Sign in / Sign up

Export Citation Format

Share Document