Electronic Structure and Phase Stability of Titanium Alloys

Morinaga, Masahiko; Yukawa, Natsuo; Adachi, Hirohiko

doi:10.2355/tetsutohagane1955.72.6_555

Cited by 54 publications

(42 citation statements)

References 17 publications

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“…Compositions of forty commercial alloys were plotted on the Bo and Md coordinates. These three types of alloys were clearly separated in the Bo and Md map 17) . Moreover, the compositional optimization of Al 21) system alloys as a simple metal were carried out by using s-orbital energy level (Mk) [13][14][15] .…”

Section: Introductionmentioning

confidence: 99%

“…In order to develop new alloys more ef ciently, a theoretical approach was strongly needed for the alloys design. The d-electrons concept on the basis of the theoretical calculation of electronic structures of alloys had been proposed on the basis of the Discrete Variational (DV)-Xα [13][14][15] cluster calculation, by Morinaga et al 16,17) . This concept was devised at rst for austenitic Ni, Co and Fe alloys, and phase boundary or some physical and chemical properties were predicted by electronic parameters.…”

Section: Introductionmentioning

confidence: 99%

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Tensile Properties of Bi Alloys and a Case Study for Alloy Design in Their Application to High Temperature Solders

Choi

et al. 2017

Mater. Trans.

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The s-orbital energy levels (Mk) of some alloying elements in a Bi cluster model were obtained on the basis of the molecular orbital calculation. In contrast, binary Bi-Cu/-Ag/-Zn system alloys with ΔMk of 0.013-0.343 were manufactured and tension-or hardness-tested, where ΔMk was the compositional average of Mk. The ultimate tensile strength and hardness were improved as alloying elements were added and increased in alloys. There was the relation between the ultimate tensile strength, fracture strain or hardness and ΔMk. Further, the compositions of Bi-2.0Ag-0.5Cu (ΔMk: 0.180), Bi-5.0Ag-0.5Cu (ΔMk: 0.379) and Bi-0.25Cu-0.25Sb (ΔMk: 0.044) were proposed as ternary alloys. It is found that the ultimate tensile strength, fracture strain and hardness values of ternary alloys could be also able to predict using their estimation lines obtained from binary Bi system alloys.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tensile Properties of Bi Alloys and a Case Study for Alloy Design in Their Application to High Temperature Solders

Choi

et al. 2017

Mater. Trans.

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“…In order to save cost and time necessary for alloy development, more fundamental approaches based on the solid theory are needed. Therefore, the d-electrons concept proposed by Morinaga 7) is applied to design of titanium alloys using ubiquitous metallic elements, in order to establish the strategic method for suppressing utilization of rare metals. The high performance metallic materials such as Ni, Ti, Al, Mg and Fe-based alloys, etc [8][9][10][11][12][13] had been developed by the d-electrons concept.…”

Section: Introductionmentioning

confidence: 99%

Alloy Design of Ti Alloys Using Ubiquitous Alloying Elements and Characteristics of Their Levitation-Melted Alloys

et al. 2010

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The + type Ti-5.5Al-2Fe and type Ti-2.5Fe-2Mn-2Zr alloys have been theoretically designed, for the modification of Ti-6Al-4V and the achievement of the high tensile strength more than 1000 MPa at the solution treatment state, respectively, using ubiquitous alloying elements in order to establish the strategic method for suppressing utilization of rare metals. The utilization of the cold crucible levitation melting (CCLM) is very useful for the production of ingots, because titanium is very chemically reactive at high temperature. The experimental alloys with high purity and without contaminations from a crucible were prepared, and the homogeneous melt was also achieved by the diffusion mixing effect of CCLM. The microstructure, phase stability, strength, corrosion-resistance and workable properties of the design Ti-5.5Al-2Fe alloy, were comparable to those of Ti-6Al-4V. In contrast, the solution heat treated Ti-2.5Fe-2Mn-2Zr alloy showed the tensile strength of 1200 MPa, and the 1.3 times increase in the specific strength compared with Ti-15Mo-5Zr-3Al. The alloy design can be successfully carried out even using ubiquitous alloying elements by the d-electrons concept, which leads to the establishment of one method for the strategic utilization of rare metals.

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“…42) Their values are not so sensitive to the crystal structure. The Bo and Md values for bcc Ti are listed in Table 2. 43)…”

Section: Titanium Alloysmentioning

confidence: 99%

“…10, about forty commercially available alloys are plotted in the BoMd diagram, by calculating the Bo and Md values from the alloy compositions. 42,44) Also, it is known that binary Ti-M alloy retains the high-temperature ¢ phase metastably even at room temperature as long as the alloy composition exceeds a certain limit. Its compositional limit varies depending on M, and such composition data, (a)³(g), are plotted on this diagram.…”

Section: Titanium Alloysmentioning

confidence: 99%

Alloy Design Based on Molecular Orbital Method

Morinaga

2016

Mater. Trans.

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A molecular orbital approach to alloy design has recently made great progress. It is based on the electronic structure calculations by the DV-X¡ cluster method, and new alloying parameters are obtained for the first time from the calculations. A theory for alloy design relevant to transition-metal based alloys have been developed using alloying parameters. For example, New PHACOMP has been developed in order to predict the formation of harmful and brittle phases (e.g., · phase) in nickel-based superalloys. A universal relation has also been discovered between electron density minima and atomic (or ionic) radii in various materials from a series of molecular orbital calculations. Furthermore, another electronic approach is explained focusing on the energy expression of the chemical bond between atoms in hydrides and hydrocarbons. All the hydrides and hydrocarbons are located on an atomization energy diagram, despite the significant differences in the nature of the chemical bond among them. One of the applications of this approach is the catalyst design. The catalytic activities of metal oxides (e.g., Nb 2 O 5 ) are evaluated quantitatively on the dehydrogenation reaction of magnesium hydride (MgH 2 ), MgH 2 ¼ Mg + H 2 .

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Electronic Structure and Phase Stability of Titanium Alloys

Cited by 54 publications

References 17 publications

Tensile Properties of Bi Alloys and a Case Study for Alloy Design in Their Application to High Temperature Solders

Tensile Properties of Bi Alloys and a Case Study for Alloy Design in Their Application to High Temperature Solders

Alloy Design of Ti Alloys Using Ubiquitous Alloying Elements and Characteristics of Their Levitation-Melted Alloys

Alloy Design Based on Molecular Orbital Method

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