Comparison of Crystalline Phases Present in Alloy Ingots, Partially Crystalline Alloys & Crystallization Products of Amorphous Alloys

1991 ◽  
Vol 38-39 ◽  
pp. 233-244
Author(s):  
E.G. Baburaj ◽  
G.K. Dey ◽  
M.D. Vora ◽  
G.E. Prasad ◽  
T. Raghu ◽  
...  
Keyword(s):  
Amorphous Alloys ◽  
Crystalline Phases

Mechanical Properties of La-based Bulk Amorphous Alloys and Composites

2002 ◽  
Vol 754 ◽  
Author(s):  
M.L. Lee ◽  
Y. Li ◽  
W.C. Carter
Keyword(s):  
Mechanical Properties ◽  
Fracture Energy ◽  
Amorphous Alloys ◽  
High Volume ◽  
Intermetallic Phases ◽  
Impact Fracture ◽  
Crystalline Phases ◽  
Bulk Amorphous Alloys ◽  
Glassy Metals ◽  
The Impact

ABSTRACTThe influence of different microstructures of La-based fully amorphous samples and its composites on the impact fracture energy were investigated and discussed. Results showed improvement in fracture energy of glassy metals with intermetallic phases, but deteriorated in the presence of dendrite phases and high volume % of crystalline phases.

ELECTRICAL RESISTIVITY OF COBALT-BORON LQA ALLOYS

1995 ◽  
Vol 09 (23) ◽  
pp. 1535-1538 ◽  
Author(s):  
S. M. M. R. NAQVI ◽  
S. DABIR H. RIZVI ◽  
SAJIDA JAMILA ◽  
SHABANA RIZVI ◽  
S. MOHSIN RAZA ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Amorphous Alloys ◽  
Amorphous Matrix ◽  
Arrhenius Plot ◽  
Amorphous Material ◽  
Activation Energies ◽  
Dangling Bonds ◽  
Crystalline Phases ◽  
Temperature Range

Activation energies determined from Arrhenius plot for cobalt-boron liquid quenched amorphous alloys in the temperature range 40 K < T < 300 K , suggest vacancy and interstitial formation to nucleate crystalline phases in an amorphous matrix preferably at sites where dangling bonds are present. Nucleation of crystallites with preferential tetragonal or orthorhombic structures is a self-evolving process due to catalytic presence of dangling bonds in an amorphous material and that the occurrence of negative activation energies support this evidence.

scholarly journals Ion milling-induced crystalline phases precipitation in multicomponent Zr-based amorphous alloys

2021 ◽  
Vol 2044 (1) ◽  
pp. 012058
Author(s):  
Yuting Feng ◽  
Jinhua Ding ◽  
Jiawei Li ◽  
Jing Ding
Keyword(s):  
Amorphous Alloys ◽  
Ion Milling ◽  
Crystalline Phases

Formation of Au-Si Metastable Phases by Ion Mixing

1981 ◽  
Vol 7 ◽  
Author(s):  
Bai-Xin Liu ◽  
Leszek S. Wieluniski ◽  
Martti MÄenpÄÄ ◽  
Marc-A. Nicolet ◽  
S. S. Lau
Keyword(s):  
Thermal Decomposition ◽  
Steady State ◽  
Thermal Annealing ◽  
Amorphous Alloys ◽  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Amorphous Structure ◽  
Metastable Phases ◽  
Formation Mechanisms ◽  
Crystalline Phases

ABSTRACTAmorphous and three metastable crystalline phases have been formed in the Au-Si system by 300 keV Xe ion mixing using multilayered samples with average compositions of Au2Si8, AuSi, and Au7 Si3. Generally speaking, during the different stages of irradiation at liquid nitrogen temperature (LNT) or room temperature (R.T.), metastable crystalline phases are formed initially, and eventually an amorphous structure is obtained. Thermal decomposition of amorphous alloys yield different metastable crystalline phases. Some of the metastable crystalline phases can be formed directly from multilayered samples by steady-state thermal annealing. The formation mechanisms of metastable phases are discussed in terms of the processes involved in ion mixing and thermal annealing.

Crystallization Behavior and Microhardness Evolution in Al92−xNi8Lax Amorphous Alloys

2005 ◽  
Vol 20 (11) ◽  
pp. 2927-2933 ◽  
Author(s):  
K.L. Sahoo ◽  
M. Wollgarten ◽  
K.B. Kim ◽  
J. Banhart
Keyword(s):  
Amorphous Alloys ◽  
Crystallization Behavior ◽  
Metastable Phase ◽  
Structural Evolution ◽  
Scanning Calorimetry ◽  
Crystalline Phases ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Three Stages ◽  
Two Stages

The crystallization behavior of melt-spun amorphous Al92−xNi8Lax (x = 4 to 6) alloys was investigated by means of differential scanning calorimetry, x-ray diffractometry, and transmission electron microscopy. Crystallization kinetics were analyzed by Kissinger and Johnson–Mehl–Avrami approaches. Microhardness of all the ribbons was examined at different temperatures and correlated with the corresponding structural evolution. The results show that the variation of La content from Al88Ni8La4 to Al86Ni8La6 has significant influence on the crystallization pathways from amorphous to stable crystalline phases and on the evolution of microhardness with temperature. The two stages of crystallization in Al88Ni8La4 and Al87Ni8La5 alloys correspond to formation of fcc-Al and Al11La3, Al3Ni, Al3La. In Al86Ni8La6, three stages of crystallization are observed which correspond to formation of a metastable phase, fcc-Al, Al11La3, Al3Ni, and Al11La3, Al3Ni, Al3La, and decomposition of a metastable phases to stable crystalline phases.

Oxygen Distribution in Zr-Based Metallic Glasses

1998 ◽  
Vol 554 ◽  
Author(s):  
D. H. Ping ◽  
K. Hono ◽  
A. Inoue
Keyword(s):  
Amorphous Phase ◽  
Metallic Glasses ◽  
Amorphous Alloys ◽  
Atom Probe ◽  
Oxygen Distribution ◽  
Crystalline Phases ◽  
Kinetics Of Crystallization ◽  
Crystallization Reaction ◽  
Impurity Oxygen ◽  
Kinetics Of

AbstractThis paper reports the atom probe analysis results of the oxygen dissolved in the as-cast amorphous and crystallized Zr65Cu15Al10Pd10 and Zr65Cul17.5Ni10Al17.5 alloys. Impurity oxygen ranging from 0.1 to 1 at.% is dissolved uniformly in the as-quenched Zr65Cu15A110Pd10 and Zr65Cu17.5Ni10Al7.5 amorphous alloys even though the oxygen is not added intentionally. When the Zr65Cu15Al10Pd10 alloy is crystallized, oxygen redistribution occurs; it is rejected from the primary Zr2 (Cu, Pd) crystals and partitioned in the subsequently crystallized phases. Oxygen atoms are enriched in some of the crystalline phases up to approximately 4 at.%, and virtually no oxygen is dissolved in the remaining amorphous phase. In the partially crystallized Zr65Cu17.5Ni10Al7.5 alloy, fine oxygen enriched particles containing ∼ 15 at.%O have been detected in direct contacted with crystalline grains. This work demonstrates that oxygen redistribution occurs during the crystallization reaction, thereby influencing the kinetics of crystallization.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

Ion Beam Mixing of Ni-Ti Bilayered Thin Films

1985 ◽  
Vol 43 ◽  
pp. 290-291
Author(s):  
A. K. Rai ◽  
R. S. Bhattacharya ◽  
M. H. Rashid
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Amorphous Alloys ◽  
Ion Beam ◽  
Ion Bombardment ◽  
High Energy ◽  
Mixing Efficiency ◽  
Ion Beam Mixing ◽  
Enhanced Diffusion ◽  
Binary Metal

Ion beam mixing has recently been found to be an effective method of producing amorphous alloys in the binary metal systems where the two original constituent metals are of different crystal structure. The mechanism of ion beam mixing are not well understood yet. Several mechanisms have been proposed to account for the observed mixing phenomena. The first mechanism is enhanced diffusion due to defects created by the incoming ions. Second is the cascade mixing mechanism for which the kinematicel collisional models exist in the literature. Third mechanism is thermal spikes. In the present work we have studied the mixing efficiency and ion beam induced amorphisation of Ni-Ti system under high energy ion bombardment and the results are compared with collisional models. We have employed plan and x-sectional veiw TEM and RBS techniques in the present work.

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