Comparison of single action die and floating die for compaction of aluminum alloy AA7075 using simulation and experimental study

Abstract

Compaction in powder metallurgy is considered to be one of the most critical steps in achieving the desired properties of green (before sintering) and final (after sintering) compacts that further play a very important role in final products manufactured using powder metallurgy. In this work, compaction was carried out using a single-action die and floating die (necessary pressure is applied from either the upper or lower punch). Simulations have been conducted with considering various loading conditions (20 to 200 kN) and friction coefficient (0 to 0.5 in the steps of 0.1) using both types of dies for manufacturing compacts of Aluminum alloy AA7075 as its demand in aerospace applications has been increased drastically in recent times. It was found from the simulated results that, to ensure satisfactory compaction using a single action die, the compaction load must be ≥100 kN, and the friction coefficient < 0.3. While, for a floating die, load ≥50 kN, and friction coefficient as zero. It was also found, that a single action die is not advisable to manufacture compact of especially Aluminum alloy AA7075 with a high aspect ratio (H/d > 1.5) in comparison with a floating die. It was also validated by experimental results. It was also observed that floating die compaction results in homogeneous physical, and mechanical properties as well as better microstructure. The compressive strength of the sintered compact is observed to be as high as 60% greater for the floating die compared to the single-action die. Moreover, it was improved by 94.14% compared to previous studies. Additionally, it was found that the effectiveness of the floating pressing die lies in its ability to achieve compaction without the complexity of a double-action system, offering practical implications for optimizing powder metallurgy processes and reducing costs.