Workability studies on cold upsetting of Al–Al2O3 composite material

Workability is concerned with the extent to which a material can be deformed in a specific metalworking process without the initiation of cracks. The ductile fracture of components is the most common mode of cracks in any metalworking processes. Workability is the complex technological concept, depends upon the ductility of the material and the details of the process parameters. An experimental research work was preformed for the understanding of the working behaviour of Al–Al2O3 composite under various stress state conditions, namely uniaxial, plane and triaxial stress states. Upsetting of Al–Al2O3 powder metallurgy compacts with various aspect ratios and initial preform densities were carried out and the working behaviour of the powder compacts at various state conditions was computed. The curves plotted for different components such as axial strain vs. formability stress index, relative density vs. axial strain, fracture strain vs. formability stress index and stress ratio parameters vs. axial strain were analyzed, using the true strains induced during upsetting with the consideration of bulging effect.