Crystal Structure and Morphology of Hydrogen Absorbing Alloys with BCC Structure

2002 ◽  
Vol 753 ◽  
Author(s):  
Akiba E. ◽  
Enoki H. ◽  
Nakamura Y.
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Intermetallic Compounds ◽  
Laves Phase ◽  
Body Centered Cubic ◽  
Hydrogen Capacity ◽  
Structure And Morphology ◽  
Bcc Structure ◽  
Cubic Structure

ABSTRACTHydrogen absorbing alloys with BCC (body centered cubic) structure such as Ti-V-Mn, Ti-V-Cr and Ti-V-Cr-Mn systems were proposed and named as “Laves phase related BCC solid solution” by Akiba in 1993. Since our reports, many researchers have developed BCC hydrogen absorbing alloys. These alloys have higher hydrogen capacity (about 2.8 mass% at present) than conventional intermetallic compounds. Many efforts have been made to increase hydrogen capacity of the alloys but fundamental studies were a few. Crystal structure and morphology of the BCC alloys that are keys to understand BCC hydrogen absorbing alloys are reviewed.

Metallic Hydrides III: Body-Centered-Cubic Solid-Solution Alloys

MRS Bulletin ◽  
2002 ◽  
Vol 27 (9) ◽  
pp. 699-703 ◽  
Author(s):  
E. Akiba ◽  
M. Okada
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Laves Phase ◽  
Body Centered Cubic ◽  
Equilibrium Pressure ◽  
Hydrogen Capacity ◽  
Structure And Morphology ◽  
Bcc Metals

AbstractHydrogen-absorbing alloys with bcc (body-centered-cubic) structures, such as Ti-V-Mn, Ti-V-Cr, Ti-V-Cr-Mn, and Ti-Cr-(Mo, Ru), have been developed since 1993. These alloys have a higher hydrogen capacity (about 3.0 mass%) than conventional intermetallic hydrogen-absorbing alloys. Generally, bcc metals and alloys exhibit two plateaus in pressure–composition isotherms, but the lower plateau is far below atmospheric pressure at room temperature. Many efforts have been made to increase hydrogen capacity and raise the equilibrium pressure of this lower plateau. The crystal structure and morphology of Laves-phase-related bcc solid-solution alloys are reviewed.

Atomvolumen und Packungsdichte der Atome in metallischen Elementen Atomic Volume and Packing Density of Atoms in Metallic Elements

2000 ◽  
Vol 55 (12) ◽  
pp. 1137-1140 ◽  
Author(s):  
Sven Hübner ◽  
Martin Trömel
Keyword(s):  
Crystal Structure ◽  
Packing Density ◽  
Maximum Density ◽  
The Body ◽  
Atomic Volume ◽  
Body Centered Cubic ◽  
Sphere Packings ◽  
Metallic Elements ◽  
Bcc Structure ◽  
Cubic Structure

In the body-centered cubic structure and in closest sphere-packings the atoms are arranged to give structures with equal densities. A measure of the packing density of atoms is derived. Several crystal structures of elements, including the bcc structure and the closest sphere packings, represent a state of maximum density in which the atomic volume is characteristic of each element. From any crystal structure of an element its atomic volume in this state can be calculated to a good approximation.

Solid-Solution Strengthening Effect of Vanadium Addition to Iron-Modified L12 Titanium Trialuminides

1994 ◽  
Vol 364 ◽  
Author(s):  
Tohru Takahashi ◽  
Tadashi Hasegawa
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Intermetallic Compounds ◽  
Argon Atmosphere ◽  
Strengthening Effect ◽  
Cubic Symmetry ◽  
Solid Solution Strengthening ◽  
Arc Melting ◽  
Solution Strengthening ◽  
Cubic Structure

AbstractTwo types of aluminum–titanium–iron–vanadium ( Al–Ti–Fe–V ) quarternary intermetallic compounds have been prepared by arc melting under argon atmosphere. Their compositions were nominally Al66Ti25Fe6V3 and Al66Ti25Fe3V6. These alloys are based on the iron–modified titanium trialuminide with L12 cubic structure. Vanadium addition up to about 6 mol% did not destroy the cubic symmetry, and L12 solid solution compounds were produced in these two Al–Ti–Fe–V quarternary alloys. Microstructure and mechanical properties have been investigated. It has been demonstrated that vanadium addition to iron–modified L12 titanium trialuminides can enhance their strength.

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