Atomic Size Effects on the Composition Range of Binary Amorphous Alloys

1986 ◽  
Vol 80 ◽  
Author(s):  
S. H. Liou ◽  
C. L. Chien
Keyword(s):  
Size Effects ◽  
Amorphous Alloys ◽  
Composition Range ◽  
Equilibrium Phase ◽  
Size Difference ◽  
Atomic Size ◽  
Atomic Size Difference ◽  
Metal Metal ◽  
Quench Method

AbstractWe have studied a number of binary metal-metal and metalloid alloy systems made by a single vapor quench method under very consistent conditions. In each case, amorphous alloys are found in one continuous composition range (Xmin<x<xXmax) regardless of the number of eutectic points in the equilibrium phase diagrams. It is found that the atomic size difference is the single most important factor in the quantitative determination of the composition range.

scholarly journals Phase selection motifs in High Entropy Alloys revealed through combinatorial methods: Large atomic size difference favors BCC over FCC

2019 ◽  
Vol 166 ◽  
pp. 677-686 ◽  
Author(s):  
Sebastian Alexander Kube ◽  
Sungwoo Sohn ◽  
David Uhl ◽  
Amit Datye ◽  
Apurva Mehta ◽  
...  
Keyword(s):  
Size Difference ◽  
High Entropy Alloys ◽  
Atomic Size ◽  
Phase Selection ◽  
High Entropy ◽  
Atomic Size Difference ◽  
Combinatorial Methods

Reassessing the atomic size effect on glass forming ability: Effect of atomic size difference on thermodynamics and kinetics

2016 ◽  
Vol 69 ◽  
pp. 123-127 ◽  
Author(s):  
Hyung-Seop Han ◽  
Nayoung Park ◽  
Jin-Yoo Suh ◽  
Ho-Seok Nam ◽  
Hyun-Kwang Seok ◽  
...  
Keyword(s):  
Size Effect ◽  
Glass Forming Ability ◽  
Size Difference ◽  
Atomic Size ◽  
Glass Forming ◽  
Thermodynamics And Kinetics ◽  
Atomic Size Difference

Investigation on Additional Hardening Mechanisms in Off-Stoichiometric Al-Rich Ni3Al Alloys in Terms of Anti-Site Defect Configuration

2002 ◽  
Vol 753 ◽  
Author(s):  
Seiji Miura ◽  
Satoshi Takizawa ◽  
Yoshinao Mishima ◽  
Tetsuo Mohri
Keyword(s):  
Flow Stress ◽  
Stoichiometric Composition ◽  
Strengthening Mechanism ◽  
Size Difference ◽  
Atomic Size ◽  
Hardening Mechanism ◽  
Atomic Size Difference ◽  
Hardening Mechanisms ◽  
Rich Side ◽  
Additional Hardening

ABSTRACTOne of the unsettled issues of the mechanical properties of L12-Ni3Al compound is the effect of off-stoichiometry on the 0.2% flow stress at low temperature region. 0.2% flow stress at 77 K increases as deviating from the stoichiometric composition to both Ni-rich and Al-rich sides, but in Al-rich side the increasing rate is higher. According to the XRD results for the binary Ni3Al alloys, however, the composition dependence of the lattice constant is the same in both sides of the stoichiometric composition, which implies that the magnitude of lattice strain induced at off-stoichiometric composition is symmetrical. And it is not rational to associate the strengthening mechanism to a sole effect of isotropic strain due to an atomic size difference. In this study, attempts are made to explain the additional strengthening in Al-rich alloys in terms of the tetragonal distortion hardening mechanism, which arises from anisotropic atomic configuration around an anti-site Al atom.

Some correlations for diffusion in amorphous alloys

1989 ◽  
Vol 4 (3) ◽  
pp. 603-606 ◽  
Author(s):  
S. K. Sharma ◽  
S. Banerjee ◽  
Kuldeep ◽  
Animesh K. Jain
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Amorphous Alloys ◽  
Published Data ◽  
Empirical Correlations ◽  
Atomic Size ◽  
Exponential Factor ◽  
Impurity Atoms ◽  
Metal Metal ◽  
Definite Correlation

Diffusion of several impurity atoms (Cu, Al, Au, and Sb) has been studied in Zr61Ni39 and Fe82B18 amorphous alloys. A definite correlation between the diffusion coefficient (D) and the atomic size of the diffusant is seen for the metal-metal (M–M) alloy, while it is not clear for the metal-metalloid (M–Me) alloy. Based on the present data, as well as other published data in binary amorphous alloys, empirical correlations have been found between (i) the activation energy (Q) and the energy required to form a hole of the size of the diffusing atom in the host alloy, and (ii) the pre-exponential factor (D0) and Q. While the former correlation is seen only for binary M–M type of amorphous alloys, the latter correlation is more general and holds for all types of amorphous alloys. Based on the correlation between D0 and Q, it is proposed that there are two distinct mechanisms of diffusion in amorphous alloys.

scholarly journals Effect of Atomic Size Difference on the Microstructure and Mechanical Properties of High-Entropy Alloys

Entropy ◽  
2018 ◽  
Vol 20 (12) ◽  
pp. 967 ◽  
Author(s):  
Chan-Sheng Wu ◽  
Ping-Hsiu Tsai ◽  
Chia-Ming Kuo ◽  
Che-Wei Tsai
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Grain Growth ◽  
Size Difference ◽  
High Entropy Alloys ◽  
Atomic Size ◽  
High Entropy ◽  
Microstructure And Mechanical Properties ◽  
Atomic Size Difference ◽  
Fcc Phase

The effects of atomic size difference on the microstructure and mechanical properties of single face-centered cubic (FCC) phase high-entropy alloys are studied. Single FCC phase high-entropy alloys, namely, CoCrFeMnNi, Al0.2CoCrFeMnNi, and Al0.3CoCrCu0.3FeNi, display good workability. The recrystallization and grain growth rates are compared during annealing. Adding Al with 0.2 molar ratio into CoCrFeMnNi retains the single FCC phase. Its atomic size difference increases from 1.18% to 2.77%, and the activation energy of grain growth becomes larger than that of CoCrFeMnNi. The as-homogenized state of Al0.3CoCrCu0.3FeNi high-entropy alloy becomes a single FCC structure. Its atomic size difference is 3.65%, and the grain growth activation energy is the largest among these three kinds of single-phase high-entropy alloys. At ambient temperature, the mechanical properties of Al0.3CoCrCu0.3FeNi are better than those of CoCrFeMnNi because of high lattice distortion and high solid solution hardening.

Solid Solution Formation Criteria for High Entropy Alloys

2007 ◽  
Vol 561-565 ◽  
pp. 1337-1339 ◽  
Author(s):  
Yong Zhang ◽  
Yun Jun Zhou
Keyword(s):  
Solid Solution ◽  
Enthalpy Of Mixing ◽  
Atomic Ratio ◽  
Size Difference ◽  
Atomic Size ◽  
Solid Solution Formation ◽  
Absolute Value ◽  
High Entropy ◽  
Solution Formation ◽  
Atomic Size Difference

The solid solution formation criteria for the equi-atomic ratio alloys were discussed. It is found that higher entropy of mixing (Smix>1.61R), less atomic size difference (δ<4.6), and near zero of the absolute value of the enthalpy of mixing (-2.685δ-2.54<Hmix <-1.28δ+5.44 KJ/mol) facilitate the formation of solid solution for the multi-principle components equi-atomic alloys.

scholarly journals Recognition of hydrogen isotopomers by an open-cage fullerene

2013 ◽  
Vol 371 (1998) ◽  
pp. 20110629 ◽  
Author(s):  
Yasujiro Murata ◽  
Shih-Ching Chuang ◽  
Fumiyuki Tanabe ◽  
Michihisa Murata ◽  
Koichi Komatsu
Keyword(s):  
Equilibrium Constants ◽  
Equilibrium Mixture ◽  
Size Difference ◽  
Binding Affinities ◽  
Kinetic Isotope ◽  
Molecular Sizes ◽  
Lower Temperature ◽  
Kinetics Of ◽  
Pressure Hydrogen

We present our study on the recognition of hydrogen isotopes by an open-cage fullerene through determination of binding affinity of isotopes H 2 /HD/D 2 with the open-cage fullerene and comparison of their relative molecular sizes through kinetic-isotope-release experiments. We took advantage of isotope H 2 /D 2 exchange that generated an equilibrium mixture of H 2 /HD/D 2 in a stainless steel autoclave to conduct high-pressure hydrogen insertion into an open-cage fullerene. The equilibrium constants of three isotopes with the open-cage fullerene were determined at various pressures and temperatures. Our results show a higher equilibrium constant for HD into open-cage fullerene than the other two isotopomers, which is consistent with its dipolar nature. D 2 molecule generally binds stronger than H 2 because of its heavier mass; however, the affinity for H 2 becomes larger than D 2 at lower temperature, when size effect becomes dominant. We further investigated the kinetics of H 2 /HD/D 2 release from open-cage fullerene, proving their relative escaping rates. D 2 was found to be the smallest and H 2 the largest molecule. This notion has not only supported the observed inversion of relative binding affinities between H 2 and D 2 , but also demonstrated that comparison of size difference of single molecules through non-convalent kinetic-isotope effect was applicable.

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