MICROSTRUCTURAL CHANGES PRODUCED IN A MULTIFILAMENTARY Nb-Ti COMPOSITE BY COLD WORK AND HEAT TREATMENT.

Abstract

The precipitates produced by heat treatment at 648 K (375 degree C) range from a thin boundary film 3 to 6 nm thick through small ellipsoidal precipitates to larger equiaxed precipitates. The larger precipitates are identified as alpha -Ti. Cold drawing refines the microstructure; an even greater degree of refinement was observed when intermediate heat treatments were applied. The observations show a strong interdependence between the cold-worked substructure and precipitate morphology in heat-treated and heavily cold-worked composites.