404 SiCウィスカ強化Al合金の引張・ねじり位相差負荷条件下の腐食疲労破壊特性(GS-11 複合材料(2))

Abstract

We describe an investigation into the fatigue fracture behaviour under combined tension-torsion loading of a SiC whisker-reinforced A6061 aluminium alloy fabricated by a squeeze casting process. Special attention was paid to the environmental effects on fatigue fracture behaviour. Tests were conducted on both the composite and its unreinforced matrix material, A6061-T6, under out-of-phase load-controlled conditions with a constant value of the combined stress ratio, α=τ_<max>/σ_<max> in a 3.5% NaCl solution at free corrosion potential. The fatigue strength in air of the unreinforced matrix material under out-of-phase combined loading was smaller than that under in-phase loading. For the composite, however, the fatigue strength under out-of-phase combined loading was higher than that under in-phase combined loading. As contrast with these, the corrosion fatigue strength of both the matrix and composite under out-of-phase combined loading was higher than that under in-phase combined loading.