Kinetic Models for the in Situ Reaction between Cu-Ti Melt and Graphite

Abstract

The in situ reaction method for preparing metal matrix composites has the advantages of a simple process, good combination of the reinforcing phase and matrix, etc. Based on the mechanism of forming TiC x particles via the dissolution reaction of solid carbon (C) particles in Cu-Ti melt, the kinetic models for C particle dissolution reaction were established. The kinetic models of the dissolution reaction of spherical, cylindrical, and flat C source particles in Cu-Ti melt were deduced, and the expressions of the time for the complete reaction of C source particles of different sizes were obtained. The mathematical relationship between the degree of reaction of C source and the reaction time was deduced by introducing the shape factor. By immersing a cylindrical C rod in a Cu-Ti melt and placing it in a super-gravity field for the dissolution reaction, it was found that the super-gravity field could cause the precipitated TiC x particles to aggregate toward the upper part of the sample under the action of buoyancy. Therefore, the consuming rate of the C rod was significantly accelerated. Based on the flat C source reaction kinetic model, the relationship between the floating speed of TiC x particles in the Cu-Ti melt and the centrifugal velocity (or the coefficient of super-gravity G) was derived. It was proven that, when the centrifugal velocity exceeded a critical value, the super-gravity field could completely avoid the accumulation behavior of TiC x particles on the surface of the C source, thereby speeding up the formation reaction of TiC x . The goal of this study is to better understand and evaluate the generating process of TiC x particles, thus finding possible methods to increase the reaction efficiency

Structural Correlation of the Glass‐Forming Ability in a Cu–Zr‐Based Metallic Glass: A Molecular Dynamics Study

“…In light of the importance of icosahedral clusters in the atomic packing and the glass transition of MGs, [ 41,42 ] it is pressing to consider the role of the full icosahedral cluster during the cooling process and its relationship to the composition. Figure 5 a demonstrates the relative fraction of the FI within the Voronoi index as function of temperature for Cu 44 Zr 52 Al 4 , Cu 42 Zr 50 Al 8 , and Cu 40 Zr 47 Al 13 MGs.…”