W-Ni-Fe焼結合金切欠材の衝撃強度

概要

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Instrumented Charpy tests were carried out for sintered W-Ni-Fe alloys in order to clarify the effects of notch radius on impact strength. Sintered 93.0W-4.9Ni-2.1Fe and 97.2W-2.0Ni-0.8Fe (in wt%)heavy alloy specimens were prepared. Notch radii of the specimens used were 1.0, 0.2 and 0.08 mm. The maximum load and the absorbed energy decreased with reducing notch radius. SEM fractography of impact specimens revealed a large amount of cleavage failure of tungsten grains. However, the absorbed energy corresponded well with the fraction of ductile fracture surface formed by the failure of matrix. Plastic strains near the fracture surface were measured by a grid method. The results indicated that the plastic zone size induced by an impact test was reduced as the notch radius decreased. On the basis of the observed plastic zone and the Rice-Rosengren-Hutchinson model, the estimated plastic works for the impact test specimens were close to the experimental absorbed energies.
一般社団法人日本機械学会の論文
1990-10-25