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NEAR‐THRESHOLD FATIGUE CRACK GROWTH IN A1 2 O 3 PARTICLE REINFORCED 6061 ALUMINIUM ALLOY
Author(s) -
Papakyriacou M.,
Mayer H. R.,
TscheggStanzl S. E.,
Gröschl M.
Publication year - 1995
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.1995.tb01190.x
Subject(s) - materials science , alloy , aluminium , paris' law , particle (ecology) , aluminium alloy , composite material , ceramic , particle size , fracture mechanics , stress (linguistics) , fracture (geology) , metallurgy , stress intensity factor , crack closure , chemical engineering , linguistics , oceanography , philosophy , engineering , geology
Abstract— The influence of Al 2 O 3 particle reinforcement on the fatigue crack growth properties of 6061‐T6 aluminium alloy in the near threshold regime has been investigated at a load ratio of R =– 1 using an alloy with 15 vol.% fine particles (6061/Al 2 O 3 /15p) and one with 21 vol.% coarser particles (6061/Al 2 O 3 /21p). The Al 2 O 3 particles act as obstacles for fatigue crack growth and are especially effective at very low cyclic loads. For the reinforced alloy with fine particles the threshold of the stress intensity amplitude is higher than that for the alloy containing coarse particles, and the lowest threshold value of K max was obtained for pure 6061‐T6. Fracture of ceramic particles and interfaces between matrix and Al 2 O 3 particles, both more frequent for coarser particles, may serve as an explanation for the more effective improvement of fatigue crack growth properties by fine particles. At maximum stress intensity factors above 6.5 MPa√m, fatigue crack growth in the particle reinforced alloys is faster than in the unreinforced alloy 6061‐T6, which is attributed to more frequent particle and interface fracturing.