ABSTRACT
I. INTRODUCTION Rapid solidification (RS) of alloys has been shown to lead to useful constitutional and microstructural effects [1]. RS allows large departures from equilibrium constitution (the identity and compositional ranges of phases formed) resulting in large extensions of solid solubility limits, formation of nonequilibrium or metastable crystalline and quasicrystalline intermediate phases, and amorphous alloys. Retention of disordered crystalline structures in normally ordered materials such as intermetallic compounds has also been reported. Additionally, RS results in changes in the morphology and dimensions of the microstructure (the size and location of the phases present) in the direction of a more uniform and finer microstructure with a large reduction in solute segregation effects. The microstructural features which are refined include grain size, dendrite arm spacing. constituent particles, and precipitates and dispersoids. Each of these attributes of RS can. either individually or in combination, contribute to a better performance of the material produced. It should be mentioned, however, that because of the "batch" nature of the RS techniques in the early years, it was difficult to envision largescale applications for these exotic products. Small-scale exploratory investigations to apply these materials in an inductance thermometer [2]. as homogeneous standards for electron probe [3] and neutron activation analysis [4]. and to monitor atmospheric pollution by sulfur dioxide [5] were carried out with some success. Some attention was also paid to potential nuclear [6] and automotive [7] applications.
