Some aspects on strain hardening behaviour in three dimensions of aluminium–iron powder metallurgy composite during cold upsetting

Strain hardening is an important phenomenon, which is required to study the plastic deformation of any material and also it is an important parameter in the study of workability criteria of metals. The present investigation has been undertaken to evaluate the strain hardening phenomenon experienced during the cold working of sintered aluminium–iron powder metallurgy composite performs during upsetting operation under various stress state conditions namely uniaxial, plane and triaxial. Sintered performs of three different aspect ratios namely 0.44, 0.45 and 0.75 with two different per cent of iron contents (0% and 2%) and with three different iron particle sizes namely −53 to +45 μm, −76 to +63 μm and −106 to +90 μm were prepared and cold forged. The strain hardening exponent ‘n’ and the strength coefficient ‘K’ were obtained for each aspect ratio and iron particle sizes. It is found that there is a greater change in the values of ‘n’ and ‘K’ for the different addition of iron powders and also for the different iron particle sizes for different aspect ratios and for different stress state conditions.