Hydrogen Depth-Profiling and Desorption Kinetics in Rapidly Solidified Al-Fe Alloys

2012 ◽  
pp. 49-54 ◽  
Author(s):  
Iya I. Tashlykova-Bushkevich ◽  
Goroh Itoh
Keyword(s):  
Depth Profiling ◽  
Desorption Kinetics ◽  
Fe Alloys ◽  
Rapidly Solidified

scholarly journals Effect of combined metal-carbon additions on the microstructure and structure of Sm2Fe17

2003 ◽  
Vol 18 (2) ◽  
pp. 279-283 ◽  
Author(s):  
B.E. Meacham ◽  
J.E. Shield
Keyword(s):  
Solute Drag ◽  
Type Structure ◽  
Drag Effect ◽  
Microstructural Refinement ◽  
Atomic Size ◽  
Alloying Additions ◽  
Grain Structures ◽  
Fe Alloys ◽  
Rapidly Solidified ◽  
Carbon Additions

The effect of combined alloying additions on the structure and scale of rapidly solidified Sm–Fe alloys was investigated. Transition metal additions tend to promote the formation of the disordered TbCu7-type structure in Sm2Fe17 alloys, as determined by monitoring the long-range order parameter. Essentially no order was observed for M = Ti, Zr, V, or Nb. Thus, the structure was close to the prototypical TbCu7-type structure. With M = Si, a large amount of order was observed (S = 0.62), resulting in a structure closer to the well-ordered Th2Zn17-type. The microstructural scale was also affected by alloying. In this case, refinement depended on the substituent and also on carbon for microstructural refinement. The scale of the as-solidified grain structures ranged from 100 nm for SiC-modified alloys to 13 nm for NbC-modified alloys. The degree of refinement was directly related to the atomic size of the M addition. The refinement was the result of solute partitioning to grain boundaries, resulting in a solute drag effect that lowered the growth rates.

The Role of Cr in H Desorption Kinetics in Rapidly Solidified Al

2014 ◽  
Vol 783-786 ◽  
pp. 264-269 ◽  
Author(s):  
Iya I. Tashlykova-Bushkevich ◽  
Keitaro Horikawa ◽  
Goroh Itoh
Keyword(s):  
High Temperature ◽  
Thermal Desorption ◽  
High Purity ◽  
Thermal Desorption Spectroscopy ◽  
Secondary Phase ◽  
Hydrogen Desorption ◽  
Oxide Surface ◽  
Desorption Kinetics ◽  
Hydrogen Trapping ◽  
Rapidly Solidified

Hydrogen desorption kinetics for rapidly solidified high purity Al and Al-Cr alloy foils containing 1.0, 1.5 and 3.0 at % Cr were investigated by means of thermal desorption analysis (TDA) at a heating rate of 3.3°C/min. For the first time, it was found that oxide inclusions of Al2O3 are dominant high-temperature hydrogen traps compared with pores and secondary phase precipitates resulted in rapid solidification of Al and its alloys. The correspondent high-temperature evolution rate peak was identified to be positioned at 600°C for high purity Al and shifted to 630°C for Al-Cr alloys. Amount of hydrogen trapped by dislocations increases in the alloys depending on Cr content. Microstructural hydrogen trapping behaviour in low-and intermediate temperature regions observed here was in coincidence with previous data obtained for RS materials using thermal desorption spectroscopy (TDS). The present results on hydrogen thermal desorption evolution indicate that the effect of oxide surface layers becomes remarkable in TDA measurements and show advantages in combinations of both desorption analysis methods to investigate hydrogen desorption kinetics in materials.

Microstructure of Rapidly Solidified Cu-Fe Alloys

1983 ◽  
Vol 28 ◽  
Author(s):  
Uwe Köster ◽  
Christoph Caesar
Keyword(s):  
Cross Sections ◽  
Contact Surface ◽  
Iron Content ◽  
Melt Spinning ◽  
Volume Fraction ◽  
Thermal Contact ◽  
Lattice Parameter ◽  
Good Thermal Contact ◽  
Fe Alloys ◽  
Rapidly Solidified

ABSTRACTRapidly solidified ribbons of Cu-Fe alloys with iron contents up to 20 at.−% have been prepared by melt-spinning. Optical and electron microscopy as well as x-ray and electron diffraction techniques were used to characterize quantitatively the microstructure, i.e., grain size and shape, solubility of iron, lattice parameter, volume fraction and distribution of precipitated iron-particles, etc.Whereas the free surfaces of melt-spun Cu-Fe ribbons have been found to be very smooth, the contact surfaces usually consist of isolated areas of good thermal contact with small equiaxed grains separated by bands without contact during casting and therefore poor heat transfer. The cross sections of the ribbons generally exhibit a strong anisotropy in their microstructure: very fine crystals adjacent to the contact surface develop into narrow columnar grains, generally significantly elongated and extending across the whole section. The average columnar width of the grains has been found to decrease significantly with increasing iron content. Precipitation of iron not only depends on the iron content but also on the distance from the contact surface.

Microstructures and phase formation in rapidly solidified Sm–Fe alloys

2003 ◽  
Vol 351 (1-2) ◽  
pp. 106-113 ◽  
Author(s):  
J.E. Shield ◽  
B.B. Kappes ◽  
B.E. Meacham ◽  
K.W. Dennis ◽  
M.J. Kramer
Keyword(s):  
Phase Formation ◽  
Fe Alloys ◽  
Rapidly Solidified

Phase transformations in rapidly solidified Nd33Fe77 alloy

1992 ◽  
Vol 50 (1) ◽  
pp. 56-57
Author(s):  
A. Zaluska ◽  
L.X. Liao ◽  
X. Chen ◽  
Z. Altounian ◽  
J.O. Ström-Olsen
Keyword(s):  
Phase Transformations ◽  
High Performance ◽  
Melt Spinning ◽  
Permanent Magnets ◽  
New Materials ◽  
Amorphous Precursor ◽  
Eutectic Melting ◽  
Subsequent Transformation ◽  
Fe Alloys ◽  
Rapidly Solidified

Nd-Fe alloys are important for high performance permanent magnets (usually in combination with B, C or N) and a knowledge of the metastable and stable phases of the system is necessary for the development of these new materials. An effective way to investigate such phases is by crystallizing an amorphous precursor.Amorphous ribbons of the binary alloy Nd33Fe77 were produced by melt-spinning. The phase transformations induced by heat treatment of the as-quenched ribbons is complex involving first the production of metastable phases followed by subsequent transformation into stable phases and finally eutectic melting.

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