Production and evaluation of spray formed MMCs

Spray forming has been proposed some 30 years ago as a method for the production of thick coatings and semi-manufactured workpieces. Despite the high costs involved in the process, increasing interest has grown regarding the utilisation of spray forming as a means for the production of huge billets of stainless steels and even superalloys, even for industrial applications. The application of such a technique for the production of spray formed thick composite specimens is considered, with particular concern to the possibility of spray forming pre-composite melt-reinforcement mixtures. Aluminium-base alloys were adopted as matrices and SiCp the reinforcement in atomisation and spray forming tests carried out in a laboratory scale gas atomizer, overcoming problems concerning the high viscosity of the mixture. Microstructural examinations and mechanical tests were carried out in order to evaluate the composite material in terms of structural homogeneity, elastic properties and strength.