Influence of Minor Cr Additions on Crystal Growth in Rapidly Solidified Al-20Zn Alloys.

It has been discovered quite recently that Icosahedral Short-Range Order (ISRO) of atoms in the liquid phase of metallic alloys surrounding some trace elements added to the melt can influence both the nucleation and growth of the primary phase. In this work, Al-20wt.%Zn alloys without and with 0.

Packing dynamics of spherical and nonconvex grains sedimenting at low Stokes number.

This paper addresses the phenomenon of random packing of sedimenting grains in the context of metallic alloy solidification from a dynamics perspective. More precisely, we investigate the evolution of the grains from the initial steady-state sedimentation until the final mechanical equilibrium-packing-is achieved. The packing dynamics of two grain geometries (spherical and nonconvex) is investigated for a hydrodynamic condition of a low ratio of grain inertia to viscous dissipation, given by a low Stokes number, St, of o(10^{-3}), which is typical in solidification.

Microsegregation Model Including Convection and Tip Undercooling: Application to Directional Solidification and Welding.

The microsegregation behavior of alloy filler metal 52 (FM 52) was studied using microprobe analysis on two different solidification processes. First, microsegregation was characterized in samples manufactured by directional solidification, and then by gas tungsten arc welding (GTAW). The experimental results were compared with Thermo-Calc calculations to verify their accuracy.

Three Dimensional Methodology to Characterize Large Dendritic Equiaxed Grains in Industrial Steel Ingots.

The primary phase grain size is a key parameter to understand the formation of the macrosegregation pattern in large steel ingots. Most of the characterization techniques use two-dimensional measurements. In this paper, a characterization method has been developed for equiaxed dendritic grains in industrial steel castings.

Packing of sedimenting equiaxed dendrites.

The packing of free-floating crystal grains during solidification has a strong impact on the phase-change process as well as on the structure and the defects in the solidified material. The packing fraction is affected by the particular dendritic morphology of the grains and by their low inertia resulting from the small density difference between solid and liquid. Understanding the grain packing phenomenon during metal alloy solidification is not experimentally possible since packing is coupled to many other phenomena.