LAUSR

Abstract The workability and the densification behavior of a porous Al–B 4 C preforms have been carried out in the present investigation. Hot upsetting tests have been carried out on Al–B 4 C powder metallurgy (P/M) preforms having an initial preform density of 0.9 and having different B 4 C compositions of 2%, 4% and 6%. The samples were compressed between two flat dies in a hydraulic press of 50 ton capacity under varying deformation temperatures such as 200 °C, 300 °C, 400 °C and 500 °C under the tri–axial stress state condition. The workability and densification behavior of Al–B 4 C preforms were analyzed till the initiation of cracks on the outer surface of the preform. The experimental results were analyzed for the various deformation parameters such as axial strain, relative density, formability stress index and different stress ratio parameter under the tri–axial stress state condition. The formability and densification behavior were discussed with the axial strain (e z ) during the hot upsetting process. The relationships between the various stress ratio parameters (σ q /σ eff, σ m /σ eff ) and formability stress index (β σ ) as a function of the relative density under the tri–axial stress state condition were established.