This work aims to study the influence of processing variables in melt spinning -which is one of the rapid solidification processes (RSP) -on the geometry of the ribbons produced directly from the melt. The R5P is one of the recent manufacturing techniques, in which the final products -ribbons and fibers -could be produced directly by solidification of liquid alloys, thus saving all further conventional metal forming processes usually carried out. In this investigation, a melt spinning apparatus

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... was designed and constructed in order to produce ribbons from the melt using a rotating substrate in the form of wheel. The alloys studied were aluminium alloys with 0, 5.23, 13.46 and 33 wt% Cu. The processing variables used were as follows: substrate linear velocity (v) ranging from 2 to 20 m.s I , injection pressure of the melt (P) ranging from 2.9 X 10 4 to 6.8 X 10 4 N.m -2 , substrate thermal conductivity (K) ranging from 43.3 to 386.6 W.m -I .K -1 , melt superheating temperature ( AT) ranging from 0 to 150 K, nozzle -substrate distance 0-0 ranging from 5 to 20 mm and nozzle diameter (d) ranging from 0.5 to 2 mm. The geometry of the product; ribbon thickness (t), width (w), length (L) and surface roughness (R t ) have been measured and they were correlated with the different processing variables. It is found that v plays the most important role in determining the geometry parameters, where a critical velocity of 5 m.s 1 is found. Varying v up to this value causes increase in w and L and a decrease in t. Increasing v beyond this value causes decrease in w, L and t. The R5P is one of the recent manufacturing techniques, in which the final products -ribbons and fibers -could be produced directly by solidification of liquid alloys, thus saving all further conventional metal forming processes usually carried out. RSP products differ from powders to continuous sheets. However, great attention is paid to powders and fibres produced by RSP techniques. Many of the jet atomization processes and chill methods have been in existence for some time on a production basis. Some examples of possible RSP products applications for military are: One of the most important applications of the RSP is the use of powders made by atomization techniques for oducing the Rapid Solidified Rate (RSR) Wafer blade [1, 2 1, which is used in turbine rotors. The pressed compacts of cast-fibres are stronger than powder cornpacts, especially when made of a strong ductile material. Such compacts will hold their shapes easily at 10% density, and will not fall apart under shock or load. Under such sever conditions, fibre compact shows little or no damage [3]. Therefore, it is probable that rolled sheets of compacted continuous aluminium fibres could readily replace lead sheets as vibrational energy absorbers, and be lighter and cheaper as well. It is also probable that such fibre sheeting would maintain its damping property over a wide range of temperatures, a performance which very few other damping materials can match. Felts and filters are, of course, other uses to which fibre compacts can be put [3 1. An untested .market for fibre sheeting is in armour. To defeat an incoming projectile, it is necessary not only to stop the forward movement of the projectile, but to absorb the shockwave produced in the armour itself by the impact before it can produce a spall from the opposite surface. The high damping fibre compacts may excell at this application [3 4 ]. A specialized market for continuous cast aluminium fibre of control.. led length is as radar chaff [ 3]. To defeat enemy radar detection, metallic dipoles (i.e., controlled-length fibres) are dispersed from an aircraft. So, it seems feasible to develop an airborn fibre-casting unit (as a chill-block melt spinning unit) capable of dispersing large quantities of dipoles of a length and cross section selected by the pilot and/or control system. Such a system could be used to detect the particular radar being used and has obvious miliitary utility.