Nucleation Behavior and Solid-Liquid Interfacial Energy of Polytetrahedral Phases

1999 ◽  
Vol 580 ◽  
Author(s):  
Dirk Holland-Moritz
Keyword(s):  
Interfacial Energy ◽  
Orthorhombic Phase ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Phase Selection ◽  
Nucleation Behavior ◽  
Σ Phase ◽  
Selection Behavior ◽  
Liquid Interfacial Energy ◽  
Solid Liquid

AbstractAccording to classical nucleation theory the nucleation- and phase-selection behavior of undercooled meltallic melts is strongly dependent on the solid-liquid interfacial energy.A structural approach to the modelling of the interfacial energy for simple melt-crystal interfaces (fcc, hcp, bcc) was developed a number of years ago [1-4]. This approach is extended to polytetrahedral phases using numerical simulation. Results of these calculations are presented for different polytetrahedral structures: the tetragonal σ-phase in Ni-V, the monoclinic phase λ-Al13Fe4, the orthorhombic phase μ-Al5Fe2 and the icosahedral quasicrystalline I-phase in Al-Pd-Mn. The numerically estimated values for the solid-liquid interfacial energy are compared with results from experiments on the undercooling- and phase-selection behavior.

scholarly journals Nucleation Behavior of a Single Al-20Si Particle Rapidly Solidified in a Fast Scanning Calorimeter

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2920
Author(s):  
Qin Peng ◽  
Bin Yang ◽  
Benjamin Milkereit ◽  
Dongmei Liu ◽  
Armin Springer ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Rapid Solidification ◽  
Heterogeneous Nucleation ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Solidification Behavior ◽  
Nucleation Kinetics ◽  
Nucleation Behavior ◽  
Nucleation Undercooling ◽  
Primary Si

Understanding the rapid solidification behavior characteristics, nucleation undercooling, and nucleation mechanism is important for modifying the microstructures and properties of metal alloys. In order to investigate the rapid solidification behavior in-situ, accurate measurements of nucleation undercooling and cooling rate are required in most rapid solidification processes, e.g., in additive manufacturing (AM). In this study, differential fast scanning calorimetry (DFSC) was applied to investigate the nucleation kinetics in a single micro-sized Al-20Si (mass%) particle under a controlled cooling rate of 5000 K/s. The nucleation rates of primary Si and secondary α-Al phases were calculated by a statistical analysis of 300 identical melting/solidification experiments. Applying a model based on the classical nucleation theory (CNT) together with available thermodynamic data, two different heterogeneous nucleation mechanisms of primary Si and secondary α-Al were proposed, i.e., surface heterogeneous nucleation for primary Si and interface heterogenous nucleation for secondary α-Al. The present study introduces a practical method for a detailed investigation of rapid solidification behavior of metal particles to distinguish surface and interface nucleation.

Solid-liquid interfacial energy on crystallization in Fe-Si-B alloy glass

1986 ◽  
Vol 21 (10) ◽  
pp. 3497-3500 ◽  
Author(s):  
Yoshitake Nishi ◽  
Kaoru Mikagi ◽  
Fumio Kanazaki
Keyword(s):  
Interfacial Energy ◽  
Alloy Glass ◽  
Liquid Interfacial Energy ◽  
Solid Liquid

Phase Selection in Sub-Rapidly Solidified Au-20Sn Alloys

2015 ◽  
Vol 817 ◽  
pp. 325-330
Author(s):  
Yu Hai Qu ◽  
Kai Jin Yang ◽  
Yan Tian Zhou ◽  
Yong Mao ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Copper Mold ◽  
Cooling Rates ◽  
Phase Selection ◽  
Graphite Mold ◽  
Injection Casting ◽  
Rapidly Solidified ◽  
Ausn Phase

The sub-rapidly solidified Au-20Sn eutectic alloys were prepared by four different solidification pathways, such as, graphite mold conventional casting, graphite mold injection casting, copper mold injection casting, and water-cooled copper mold suction casting. The precipitating sequences of competing primary phases of sub-rapidly solidified Au-20Sn alloys with four different cooling rates were investigated. The results show that phase selection process is related to the cooling rates during sub-rapid solidification process. The primary ζ'-Au5Sn phase with developed dendrites precipitate at low cooling rate (2.4×10−4.2×102K/min) and the morphologies of the primary ζ'-Au5Sn change to rosette-like at higher cooling rate (9.0×103K/min). While the cooling rate reaches to 3.5×104K/min, the primary ζ'-Au5Sn phase can be suppressed but δ-AuSn phase will precipitate prior to the ζ'-Au5Sn phase. On the basis of the classical nucleation theory and transient nucleation theory, the process of competitive nucleation between the ζ'-Au5Sn phase and the δ-AuSn phase were analyzed for sub-rapid solidified Au-20Sn alloy. The theoretical calculations are consistent with the experimental investigations.

The Effects of Si on the Nucleation Kinetics of Ferrite in Dual Phase Steels

2007 ◽  
Vol 26-28 ◽  
pp. 1307-1310 ◽  
Author(s):  
Sang Hwan Lee ◽  
Kyung Jong Lee
Keyword(s):  
Free Energy ◽  
Interfacial Energy ◽  
Free Energy Change ◽  
Nucleation Theory ◽  
Energy Change ◽  
Classical Nucleation Theory ◽  
Nucleation Kinetics ◽  
Kinetics Of ◽  
Volume Free Energy Change ◽  
Thermodynamic Factors

It is generally accepted that Si promotes kinetics of polygonal ferrite due to thermodynamic factors such as Ae3 and maximum amount of ferrite formed. However, in this study, it was found that the difference between the measured rates of ferrite formation in C-Mn steel and Si added steel was much larger than that expected considering only thermodynamic factors. The classical nucleation theory with pillbox model was adopted to figure out what is the most controlling factor in formation of ferrite. The volume free energy change was calculated by use of the dilute solution model. The diffusivity of carbon (DC) was formulated as functions of C, Mn and Si by using experimental data. It was found that the volume free energy change was still predominant but the kinetic factors such as interfacial energy and the diffusivity of carbon by addition of Si were not negligible at lower undercooling. However, with increasing undercooling, the diffusivity of C was the most effective on the ferrite kinetics, though the ambiguity of treating interfacial energy was not yet clear.

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