Effect of pre-compaction stage parameters on the defects occurred during post compaction stage in aluminum foams fabricated via powder metallurgy using carbamide space holders

Acceptance of a newly developed material into the industry highly depends upon its characteristics and ability to produce consistently and efficiently based on the needs. Metal foams are the materials facing difficulties getting adopted because of their structural randomness. Metal foam offers very unique property combinations, but it is difficult to maintain consistent production. Foam produced by the powder metallurgy method using the space holder helps achieve the desired pore morphology and characteristics. Every process step demands attention to ensure the quality. The manufacturing process can be divided into two parts based on the state of the raw material, i.e., (1) pre-compaction and (2) post-compaction stage. During the water leaching, a post-compaction stage process, samples exhibiting the spalling issue have direct relevance to the raw material produced at the pre-compaction stage. In this investigation, an attempt has been made to systematically investigate the effects of the pre-compaction stage process on the defects encountered during the post-compaction stage. The mechanisms are discussed in detail, where the root cause for the occurrence of a particular defect lies in the pre-compaction stage process, mainly space holder mixing and die-filling. Major Findings: A defect caused by the foam production method and material conditions, spalling is a post-compaction phenomenon with roots in the pre-compaction stage. The overall quality and structural integrity of aluminium metal foam are largely determined by important pre-compaction parameters, such as die filling, time interval, mixing procedure, and binder addition.