金属粉末の圧縮成形に関する研究-2-三軸圧縮装置による成形条件の検討

概要

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Three dimensional compaction is carried out to determine a compaction criterion for metal powders. Compaction is attempted under various strain ratios or stress ratios. It is thereby confirmed that the compaction criterion is expressed by F=√1/2{(σ1-σ2)2+(σ2-σ3)2+(σ3-σ1)2}+(σmlf)2, where σ1, σ2 and σ3 are three principal stresses, f and F are functions of density ratio. In case of copper powders tested f=1/2√1-γ and F=46.7γ2.5⋅ The compaction criterion appears to be a plastic potential which leads to a stress-strain relationship expressed by dεi=dλ{σi-(1-2/9f2)σm} (i=1, 2, 3). The above equations are utilized to calculate a pressure versus density ratio in closed-die compaction, which shows a good agreement with the experimental results.
社団法人粉体粉末冶金協会の論文