scholarly journals Crystallization behavior of Zr62Al8Ni13Cu17 Metallic Glass

2017 ◽  
Vol 62 (2) ◽  
pp. 1023-1026 ◽  
Author(s):  
Mi Sun Jo ◽  
Jin Kyu Lee
Keyword(s):  
Metallic Glass ◽  
Crystalline Phase ◽  
Crystallization Behavior ◽  
Amorphous Matrix ◽  
Primary Crystallization ◽  
Isothermal Transformation ◽  
Avrami Analysis ◽  
Diffusion Controlled ◽  
Residual Amorphous Matrix ◽  
Glass Alloy

AbstractThe crystallization behavior has been studied in Zr62Al8Ni13Cu17metallic glass alloy. The Zr62Al8Ni13Cu17metallic glass crystallized through two steps. The fcc Zr2Ni phase transformed from the amorphous matrix during first crystallization and then the Zr2Ni and residual amorphous matrix transformed into a mixture of tetragonal Zr2Cu and hexagonal Zr6Al2Ni phases. Johnson-Mehl-Avrami analysis of isothermal transformation data suggested that the formation of crystalline phase is primary crystallization by diffusion-controlled growth.

TEM INVESTIGATION ON CRYSTALLIZATION BEHAVIOR OF A Fe68C10.5Si4.4B6.5P8.6Al2 BULK METALLIC GLASS

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1223-1228
Author(s):  
KI BUEM KIM ◽  
HONG XIANG LI ◽  
SEONGHOON YI
Keyword(s):  
Heat Treatment ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Crystallization Behavior ◽  
Amorphous Matrix ◽  
Treatment Time ◽  
Annealing Treatment ◽  
Primary Crystallization ◽  
Heat Treatment Time ◽  
Nano Scale

TEM investigations on crystallization behavior of a Fe 68 C 10.5 Si 4.4 B 6.5 P 8.6 Al 2 bulk metallic glass reveals that the nano-scale fcc Fe phase formed by primary crystallization is homogeneously embedded in the amorphous matrix after heat treatment at 783 K for 30 min. With increasing heat treatment time (783 K for 45 min), a tetragonal Fe 3( C , B , P ) phase encapsulates the primary fcc Fe phase suppressing the growth of the fcc Fe phase. The Fe 3( C , B , P ) phase decomposes into a mixture of orthorhombic Fe 3( C , P ) and tetragonal Fe 3( B , P ) upon further annealing treatment at 783K.

Contact Reactions at Cu / a-Ge Thin Film Couples

1993 ◽  
Vol 311 ◽  
Author(s):  
Uwe KÖster ◽  
Klaus P. Blennemann ◽  
Axel Schulte
Keyword(s):  
Thin Film ◽  
Driving Force ◽  
Amorphous Matrix ◽  
Primary Crystallization ◽  
Contact Reaction ◽  
Cross Sectional ◽  
Fine Grained ◽  
Transmission Electron ◽  
Diffusion Controlled ◽  
Cu Film

ABSTRACTThe aim of this paper is to investigate phase formation and growth kinetics in thin film Cu/a-Ge difflusion couples (150 nm Cu / 150 nm Ge) by means of cross-sectional transmission electron microscopy. During annealing in the temperature range between 100 and 180°C a highly supersaturated ζ-phase was formed first; the growth of this phase exhibits a parabolic dependence, thus indicating diffusion controlled growth; further annealing leads to a transformation into the orthorhombic ε1-phase. The first phase formed during the contact reaction probably depends on the texture and orientation of the copper layer with (111) Cu favouring the formation of the ζ-phase. When in contact with crystalline Ge the orthorhombic ε1-phase is formed directly, probably caused by a lack of driving force for the formation of the ζ-phase.Crystallization of Cu-contaminated amorphous Ge is characterized by the formation of an extremely fine-grained microstructure; higher Cu contents lead to primary crystallization of the ε1-phase (orthorhombic Cu3Ge) followed by polymorphous crystallization of the amorphous matrix into crystalline Ge. These results indicate that the early formation of a crystalline interlayer is not due to the reduced crystallization temperature of an amorphous Ge(Cu) film as formed by Cu diffusion into the amorphous Ge.

Thermal Stability and Crystallization Kinetics of Ti40Zr10Cu34Pd14Sn2 Bulk Metallic Glass

2012 ◽  
Vol 188 ◽  
pp. 3-10 ◽  
Author(s):  
Mariana Calin ◽  
Mihai Stoica ◽  
Na Zheng ◽  
Xiao Rui Wang ◽  
Sergio Scudino ◽  
...  
Keyword(s):  
Activation Energy ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Crystallization Process ◽  
Primary Crystallization ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Scanning Calorimetry ◽  
Diffusion Controlled

In this work, the isochronal and isothermal activation energies for the primary crystallization process of Ti40Zr10Cu34Pd14Sn2bulk metallic glass have been studied by differential scanning calorimetry and determined using the Kissinger approach and the Johnson-Mehl-Avrami analysis, respectively. The activation energy for crystallization evaluated by the Kissinger method is 253 kJ/mol. Similar activation energy for crystallization was obtained from the viscosity measurements. The values of the differential Avrami exponent are also determined from the isothermal data. Assuming diffusion-controlled growth, it is shown that thermal treatment of the samples in the supercooled liquid region considerably influences the behavior of the nucleation rate during the crystallization process.

The effect of Ti, Nb, and Ta additions to ZrAlCu metallic glass on the crystallization and formation of the icosahedral phase

2007 ◽  
Vol 22 (4) ◽  
pp. 1093-1097 ◽  
Author(s):  
J.B. Qiang ◽  
W. Zhang ◽  
G.Q. Xie ◽  
A. Inoue
Keyword(s):  
Transition Metals ◽  
Metallic Glass ◽  
Phase Formation ◽  
Crystallization Behavior ◽  
Alloy System ◽  
Primary Crystallization ◽  
Icosahedral Phase ◽  
Necessary Condition ◽  
Present Alloy ◽  
Heats Of Mixing

The addition of Ti, Nb, or Ta altered the crystallization behavior of the Zr65Al7.5Cu27.5 glass, and a metastable nanoscaled I-phase was obtained on primary crystallization of these quaternary glasses. The complete substitution of Al by Nb also led to the precipitation of I-phase upon crystallization. Negative heats of mixing between the addition metals and the transition metals of the mother alloy were demonstrated to be not a necessary condition for I-phase formation in the present alloy system.

Crystallization Behavior of an Au Based Metallic Glass at High Temperature

2019 ◽  
Author(s):  
F.X. Bai ◽  
S.J. Zheng ◽  
Y.X. Wang ◽  
J. Pan ◽  
J.H. Yao ◽  
...  
Keyword(s):  
High Temperature ◽  
Metallic Glass ◽  
Crystallization Behavior

Influence of Pressure on the Crystallization in SiO2f/SiO2 Composites

2007 ◽  
Vol 336-338 ◽  
pp. 1236-1238
Author(s):  
Chang Ming Xu ◽  
Shi Wei Wang ◽  
Xiao Xian Huang ◽  
Jing Kun Guo
Keyword(s):  
Phase Composition ◽  
Crystalline Phase ◽  
Hot Pressing ◽  
Crystallization Behavior ◽  
Nucleation Mechanism ◽  
Composition Analysis ◽  
Pressing Pressure ◽  
Surface Nucleation ◽  
Bulk Nucleation ◽  
Phase Composition Analysis

The influence of pressure on the crystallization behavior in SiO2f/SiO2 composites hotpressed at 1350°C was studied. The crystalline phase composition analysis on SiO2f/SiO2 composites revealed that the formation of cristobalite was promoted when the hot-pressing pressure ≤ 12 MPa, however suppressed with higher pressure applied. It can be ascribed to the nucleation mechanism change from surface nucleation to bulk nucleation. Analysis on relative density as well as fracture microstructure of SiO2f/SiO2 composites confirmed the conclusion.

Influence of sub-Tg annealing on microstructure and crystallization behavior of TiZr-based bulk metallic glass

2021 ◽  
Vol 565 ◽  
pp. 120855
Author(s):  
J.W. Lv ◽  
D.W. Yin ◽  
F.L. Wang ◽  
Y.J. Yang ◽  
M.Z. Ma ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Crystallization Behavior

Two-Stage Crystallization Of Poly (Ether Ether Ketone) And Its Blends With Poly (Ether Imide)

1993 ◽  
Vol 321 ◽  
Author(s):  
Hsin-Lung Chen ◽  
Roger S. Porter
Keyword(s):  
Crystallization Rate ◽  
Primary Crystallization ◽  
Secondary Crystallization ◽  
Comparable Rate ◽  
Diffusion Controlled ◽  
Crystallization Region ◽  
Ether Ether Ketone ◽  
Poly Ether Ether Ketone ◽  
Controlled Crystallization ◽  
Ether Ketone

ABSTRACTThermal Mechanical analysis (TMA) has been used to study the crystallization behavior of poly (ether ether ketone) (PEEK) and its blends with poly (ether imide) (PEI). The two crystallization stages of PEEK are clearly distinguished by measuring the variation of film thickness with time during isothermal crystallization. Upon blending with PEI, the distinction of the two PEEK crystallization stages becomes obscure. This is attributed to the depressions in both nucleation density and spherulite growth rate upon blending with PEI.An Avrami analysis, Modified by considering both primary and secondary crystallization, is used to extract the respective kinetic behavior of these two crystallization stages. The results indicate that the secondary crystallization proceeded slower than the primary crystallization in the diffusion-controlled crystallization region. On the other hand, these two crystallization stages proceeded at comparable rate in the thermodynamically-controlled crystallization region. It is also found in the diffusion-controlled crystallization that blending with PEI induced a larger depression in the secondary crystallization rate than in the primary crystallization rate. Explanations for these observations are proposed and discussed.

Refinement of Size Distributions for Primary Crystallizations

1997 ◽  
Vol 481 ◽  
Author(s):  
E. Pineda ◽  
T. Pradell ◽  
D. Crespo ◽  
N. Clavaguera ◽  
J. ZHU ◽  
...  
Keyword(s):  
Grain Size ◽  
Metastable Phase ◽  
Primary Crystallization ◽  
Controlled Growth ◽  
Diffusion Controlled ◽  
Average Grain Size ◽  
Soft Impingement ◽  
Single Grain ◽  
Kinetics Of ◽  
And Diffusion

ABSTRACTThe microstructure developed in primary crystallizations is studied under realistic conditions. The primary crystallization of an amorphous alloy is modeled by considering the thermodynamics of a metastable phase transition and the kinetics of nucleation and crystal growth under isothermal annealing. A realistic growth rate, including an interface controlled growth at the beginning of the growth of each single grain and diffusion controlled growth process with soft impingement afterwards is considered. The reduction in the nucleation rate due to the compositional change in the remaining amorphous matrix is also taken into account. The microstructures developed during the transformation are obtained by using the Populational KJMA method, from the above thermodynamic and kinetic factors. Experimental data of transformed fraction, grain density, average grain size, grain size distribution and other related parameters obtained from annealed metallic glasses are modeled.

Sign in / Sign up

Export Citation Format

Share Document