アルミニウムの疲労損傷に及ぼす試験温度の影響

概要

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The effect of test temperature on fatigue damage was studied on pure aluminium in fully reversed plane bending by using the X-ray microbeam technique. As a result, the fatigue strength was found to decrease with increasing test temperature. As the test temperature was elevated, the total misorientation β, the excess dislocation density (D_b)_<max> and (D_b)_<min> increased, and larger and more polygonized subgrains were formed. This resulted in the reduction of fatigue strength. The propagation rate of fatigue crack dl/dN was dependent on test temperature and hot uniquely expressed by a power function of the stress intensity factor. However, the excess dislocation density (D_b)_<max> and the subgrain size t in the grain at crack tip were closely related to the crack propaga-tion rate dl/dN by the following equations independently of test temperatures: dl/dN=3.26 ×10^<-24> (D_b)_<max> <1.79> and dl/dN=3.08×10^<-3> t^<-3.69>.
1977-01-15