An analysis of the crystallographic orientation of polycristalline silicon ingots, obtained by a directional solidification in carbon crucible according to Bridgman method using no seed crystal, is described. The grain growth, in alignment with the higher temperature gradient, produces different crystallized zones in the ingot : an axially columnar structure in the middle and a radial dentritic...

Chaput Kevin J. Ph.D., Purdue University, May 2015. Near-Congruent Solidification of Castings. Major Professor: Kevin Trumble. A study on the microstructure development of as-cast Cu-Mn alloys based around the congruent minimum at 34.6 wt % Mn and 873 oC was performed. Initially, this was to evaluate the alloy as an alternative to wide freezing range Pb and Sn bronzes that are plagued with poro...

Using scanning and transmission electron microscopy, we studied silicon particles formed during the solidification of Al-7%Si alloy when different modifying mixtures were introduced into the melt: (1) a mixture of ultrafine powders Na3AlF6 + K2ZrF6 + TiO2 + ZrO2; (2) K2ZrF6; and (3) the flux Arsal. By differential scanning calorimetry, it was established that modifying mixtures significantly in...

Two distinct and novel formalisms for deriving exact closed solutions of a class of variable-coefficient differential-difference equations arising from a plate solidification problem are introduced. Thereupon, exact closed traveling wave and similarity solutions to the plate solidification problem are obtained for some special cases of time-varying plate surface temperature.

In the present study, the microstructure of welded zone of Hastelloy X sheets with thickness of 1 mm via pulsed Nd-YAG laser welding were studied. This welding process was done by autogenus and conductive method. Microstructure were observed by metallurgical OM and SEM. Results shown Solidification of the weld metal is dendritic. The dendrites in the central zone of the welding are fine and equ...

Cracking is a major concern in welding aluminum alloys. Although weld solidification cracks can be eliminated through addition of filler alloy, the additives modify the alloy or base-metal constituents and may not always be desirable. High-energy beam processes, such as electron-beam welding, that result in minimal heat input reduce crack sensitivity, but their high cost limits their applicatio...

We describe a model for non-convecting diffusion-controlled solidification of a ternary (three-component) alloy cooled from below at a planar boundary. The modelling extends previous theory for binary alloy solidification by including a conservation equation for the additional solute component and coupling the conservation equations for heat and species to equilibrium relations from the ternary...