Formation Mechanisms, Detection Techniques, and Mitigation Methods of Defects in Powder Metallurgy Products

Powder metallurgy, as an advanced manufacturing technology featuring near-net shaping and high efficiency and energy conservation, plays an irreplaceable role in high-end equipment fields such as aerospace, automotive, and electronics. However, during the preparation of powder metallurgy products, various defects are prone to occur, which seriously restrict the performance and reliability of the products. Therefore, this paper reviews the formation mechanism, detection technology and mitigation methods of key defects in powder metallurgy products. Firstly, the defects are classified into common defects such as stomata, cracks and inclusions, as well as special defects such as original particle boundaries (Prior Particle Boundary,PPB), delamination and segregation. Influences of the characteristics of the original powder and powder metallurgy process parameters on the formation of various defects are analyzed. Then, the microscopic and macroscopic detection methods of various defects are summarized, covering conventional destructive testing and non-destructive testing techniques. In terms of defect mitigation, this paper summarizes the suppression methods of various defects in different alloy systems, mainly involving powder surface modification, optimization of molds and pressing curves, advanced densification technologies and targeted heat treatment techniques. Finally, this paper looks forward to the prospects of the deep integration of this field with material gene engineering, artificial intelligence and digital twins, aiming to provide theoretical guidance for the quality control and performance improvement of powder metallurgy products.