Masafumi Miyajima1, Akira Kawasaki2 and Ryuzo Watanabe2
1Graduate Student, Tohoku University, Sendai
Densification and microstructural development of stainless steel powder compacts during hot powder vehicle compaction was investigated. The preheated powder preform, vacuum encapsuled in a borosilicate glass, was compacted in a steel die using preheated alumina granules as a pressure transmitting medium. The condition for the fun-densification was determined as a function of pressure and temperature. Three microstructural features were observed during the compacting process; solutioning of dendritic structure, recrystallization and normal grain growth, which in turn was found to be mainly dependent on preheating temperature. It has been found that a submicron-sized micro-structure is formed during the recrystallization stage. The densification mechanism of the present compaction process has been discussed on the basis of a concept of pressure sintering map.
hot powder vehicle compaction, full-densification, stainless steel powder, submicron-sized microstructure
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