Dependence of the intragrain structure of (?+?)-titanium alloys on chemical composition and cooling rate during phase recrystallization

1991 ◽  
Vol 33 (12) ◽  
pp. 893-895
Author(s):  
G. A. Bochvar
Keyword(s):  
Chemical Composition ◽  
Titanium Alloys ◽  
Cooling Rate ◽  
Phase Recrystallization

Thermal Parameters, Microstructure and Porosity During Transient Solidification of Ternary Al–Cu–Si Alloys

2012 ◽  
Vol 730-732 ◽  
pp. 883-888 ◽  
Author(s):  
Daniel J. Moutinho ◽  
Laércio G. Gomes ◽  
Otávio L. Rocha ◽  
Ivaldo L. Ferreira ◽  
Amauri Garcia
Keyword(s):  
Growth Rate ◽  
Chemical Composition ◽  
Cooling Rate ◽  
Tip Growth ◽  
Thermal Parameters ◽  
Volumetric Fraction ◽  
Dendritic Network ◽  
Intermetallic Particles ◽  
Casting Length

Solidification of ternary Al-Cu-Si alloys begins with the development of a complex dendritic network typified by primary (λ1) and secondary (λ2) dendrite arm spacings which depend on the chemical composition of the alloy and on the casting thermal parameters such as the growth rate and the cooling rate. These thermal parameters control the scale of dendritic arms, the size and distribution of porosity and intermetallic particles in the casting. In this paper, λ1and λ2were correlated with experimental thermal parameters i.e., the tip growth rate and the tip cooling rate. The porosity profile along the casting length has also been experimentally determined. The volumetric fraction of pores increase with the increase in alloying Si and with the increase in Fe concentration at the regions close to the casting cooled surface.

Microstructure and Mechanical Properties of Al-12.6%Si Composite Reinforced by Al63Cu25Fe12Quasicrystal

2012 ◽  
Vol 182-183 ◽  
pp. 162-166
Author(s):  
Can Can Li ◽  
Hao Ran Geng ◽  
Zhen Yuan Li ◽  
Hai Ou Qin
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Cooling Rate ◽  
Quasicrystalline Phase ◽  
Melt Temperature ◽  
Microstructure And Mechanical Properties

In this paper, Al-12.6%Si/Al63Cu25Fe12 composites were fabricated by method of casting. The microstructure and chemical composition of Al63Cu25Fe12 quasicrystal alloy and Al-12.6%Si alloy reinforced by the quasicrystal were studied, and the mechanical properties of Al-12.6%Si composite were also measured. The results show that almost single quasicrystalline phases exist in the samples which are cast with the 1300°C melt. Quickly enough cooling rate and appropriate melt temperature are necessary for the formation of the quasicrystalline phase. In addition, Al-12.6%Si composite has optimal mechanical properties when the amount of Al63Cu25Fe12 quasicrystal is 3 wt%.

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.

Comparative study of the oxide scale thermally grown on titanium alloys by ion beam analysis techniques and scanning electron microscopy

2008 ◽  
Vol 23 (8) ◽  
pp. 2245-2253 ◽  
Author(s):  
A. Gutiérrez ◽  
F. Pászti ◽  
A. Climent-Font ◽  
J.A. Jiménez ◽  
M.F. López
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Composition ◽  
Titanium Alloys ◽  
Oxide Scale ◽  
Ion Beam ◽  
Elastic Recoil ◽  
Detection Analysis ◽  
Nb Content ◽  
Scanning Electron

In the present work, the oxide layers developed at elevated temperature on three vanadium-free titanium alloys, of interest as implant biomaterials, were studied by Rutherford backscattering spectroscopy, elastic recoil detection analysis, and scanning electron microscopy. The chemical composition of the alloys investigated, in wt%, was Ti–7Nb–6Al, Ti–13Nb–13Zr, and Ti–15Zr–4Nb. Upon oxidation in air at 750 °C, an oxide scale forms, with a chemical composition, morphology, and thickness that depend on the alloy composition and the oxidation time. After equal exposure time, the Ti–7Nb–6Al alloy exhibited the thinnest oxide layer due to the formation of an Al2O3-rich layer. The oxide scale of the two TiNbZr alloys is mainly composed of Ti oxides, with small amounts of Nb and Zr dissolved. For both TiNbZr alloys, the role of the Nb-content on the mechanism of the oxide formation is discussed.

Features of Amorphization of the Fe-TM-Nd-REM-B Alloys System at Melt Quenching by Gas Atomization

2019 ◽  
Vol 31 ◽  
pp. 51-55
Author(s):  
Mikhail Sorokovikov ◽  
Valeriy V. Savin ◽  
Ludmila A. Savina ◽  
V.A. Chaika ◽  
I.S. Zherebcov
Keyword(s):  
Chemical Composition ◽  
Cooling Rate ◽  
Primary Crystallization ◽  
Primary Phase ◽  
Gas Atomization ◽  
Spherical Powder ◽  
Similar Chemical ◽  
Powder Particles ◽  
The Moment ◽  
Triple Eutectic

Gas atomization powders (GAP) chemical composition which corresponds to the first area of the phase equilibrium, and the fraction that ensures a cooling rate of a separate powder particle of more than 103K/s contains an amorphous component of two types: the first (AC1) has a chemical composition similar to that of the alloy; and the second (AC2) has a chemical composition of the triple eutectic. AC1 is mostly localized on the surface of the powder particles (in the form of layers, shells, nodules) or are detected in the whole volume of the spherical powder particles with its size less than 5 μm. The authors hold that during gas atomization, powder particles of this size have a cooling rate ≥ 105 K/s. Alloys having a similar chemical composition at similar cooling rates are also amorphized by quenching from the liquid state. This proves that an amorphous alloy of the first type is formed directly from a supercooled melt. While AC2 (enriched by Nd) is formed on the border or in the between the crystal phase Fe14Nd2B of the remaining (after primary crystallization during the primary phase) melt enriched by the moment of the solidification of Nd.

scholarly journals 5. The Chemical Relationship between Howardites and the Silicate Fraction of Mesosiderites

1977 ◽  
Vol 39 ◽  
pp. 445-450
Author(s):  
A. B. Simpson ◽  
L. H. Ahrens
Keyword(s):  
Chemical Composition ◽  
Cooling Rate ◽  
Major Elements ◽  
Parent Body ◽  
Common Parent ◽  
Silicate Fraction

Analyses of eleven major elements in five howardite samples and in the silicate fraction of seven mesosiderites are presented in a recalculated form and compared. The mesosiderite silicate fractions show distinct differences in chemical composition from the howardites, but the average Ca/Al determined for mesosiderites (1.05), which differs from most values previously published, is close to that typical of howardites (1.08). The inverse Ca/Mg relationship in the howardites is present also in the mesosiderites, the trend being displaced relative to that of the howardites but parallel to it. The chemical differences confirm that mesosiderites are not mixtures of howardite and metal. The Ca/Al and Ca/Mg relationships suggest that the two meteorite groups were subject to similar genetic controls, and may therefore have had a common parent body. Such a body is required by the cooling rate of the metal of mesosiderites to have been larger than any known asteroid.

scholarly journals Influence of the Cooling Rate on the Morphology of Spheroidic Graphite Obtained by the CO2 Process

2013 ◽  
Vol 8 (22) ◽  
pp. 37
Author(s):  
Mauro Carlos Souza ◽  
Antonio Carlos de Araújo Santos ◽  
Wilma Clemente de Lima Pinto ◽  
Mila Rosendal Avelino
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Chemical Analysis ◽  
Cooling Rate ◽  
Processing Parameters ◽  
Mechanical Resistance ◽  
Metallic Materials ◽  
Metallurgical Processing ◽  
Resistance Tests

The mechanical properties of cast metallic materials are strongly influenced by processing parameters, such as percentage of silicate, sand granulometry, and metallurgical processing. The ductile iron cast produced by the CO2 process depends on variables that determine the behavior of the material in service, such as the cooling rate and chemical composition. This study evaluated the influence of the cooling rate on the spheroidic graphite. In order to determine this effect, a simulation was performed in specimens with 20, 25, and 30 mm in thickness, through the characterization of type, measurement of nodule size, and distribution of nodules. Chemical analysis and mechanical resistance tests were performed. The 25 mm thick specimen showed the best behavior among the three thicknesses evaluated, presenting the formation of many small nodules and a small amount of larger nodules in the center.

Weld Repair of Shell Plates During Seagoing Operations

2002 ◽  
Author(s):  
Per R. M. Lindstro¨m ◽  
Anders Ulfvarson
Keyword(s):  
Grain Size ◽  
Theoretical Model ◽  
Chemical Composition ◽  
Cooling Rate ◽  
Base Material ◽  
Forced Flow ◽  
Welding Parameters ◽  
Weld Repair ◽  
Welding Seam ◽  
Welding Procedure

An algorithm to estimate the cooling rate of welding seams on the shell plating of a ship, below the waterline, while it is on voyage has been derived. The demand for this technique has arisen from the wish of ship operators to make it possible for the safe repair of ship structures without taking them out of operation. [1] The strength of the shell plating after welding is determined by its metallurgic structure, which is dependent on the cooling rate, its chemical composition and the original grain size of the base material. [2] The cooling rate for this type of welding seam depends on the velocity of the water flow, the distance from the bow, the thickness of the plate, and the heat from the heat input of the welding. The algorithm makes it possible to calculate the cooling rate for a base material affected by a forced flow of fluid by means of Rosenthal’s equation and thus enabling suitable welding parameters to be determined. As the welding parameters can be chosen to fit the specific repair to be made, it is now possible to determine the suitability of a welding procedure in advance. The algorithm is applicable when determining welding parameters at Hot-Tapping operations as well, where the base material is affected by a forced flow of fluid. A number of experiments have been performed and the results support the theoretical model. The research project continues with the aim of finding an algorithm to include the enhanced cooling rate due to the layer of boiling fluid on the back of the base material. A method to improve the measurements of the most important parameter in the algorithm has been developed and makes it possible to build up a quantitative database of typical values for various configurations.

Sign in / Sign up

Export Citation Format

Share Document