Rapid Solidification Under Pressure

Another homemade apparatus was designed and assembled with the aim of obtaining polymer samples solidified under known temperatures and pressure histories [32,33]. The apparatus, based on the confining fluid techniques, applies hydrostatic pressure on the sample during fast solidification. 

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A. Purification of phenanthrene. 1. By azeotropic distillation.2 A mixture of 300 g. of commercial phenanthrene (Note 1), 90 g. of maleic anhydride, and 600 ml. of xylene, contained in a 2-1. round-bottomed flask, is heated under reflux for 20 hours (Note 2). The initially yellow solution rapidly turns to a dark brown on heating. This solution is cooled to room temperature and filtered by suction to remove any insoluble adduct. The filtrate is then extracted with two 100-ml. portions of dilute sodium hydroxide, and the basic extracts are discarded. The organic phase is next washed with water and saturated sodium chloride solution, and finally is filtered through a layer of anhydrous magnesium sulfate. The excess xylene is removed by distillation, first at atmospheric pressure then the final portions are removed at reduced pressure. The residue, while still hot, is poured into a large mortar and, after solidification, is powdered to a convenient size. The yield of crude phenanthrene is 230-240 g. 

Pressure die casting, which permits economical production of intricate castings at a rapid rate. In this process molten metal is forced into a mold under considerable pressure. The pressure is maintained until solidification is complete. 

Conventional solidification, annealing at high temperature and rapid quenching from the melt (p) were used to obtain precursor alloys exhibiting well defined microstructures. The rapid quenching was performed under helium atmosphere. The temperature of the melt before ejection was kept at about 1560°C. The influence of the ejection pressure and the rolling velocity on the microstructure have been reported previously (5,6). Undoped and doped Ni2 i MxAl3 base alloys were tested (M = Cr, Cu). 

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