学術雑誌論文

6061Ｔ6アルミニウム合金の高ひずみ速度域１×103s-1から４×104s-1における変形応力のひずみ速度依存性

Strain Rate Dependence of Dynamic Flow Stress of 6061-T6 Aluminum Alloy at Strain Rates Ranging from 1×10 3to4×10 4s-1

jpn

社団法人日本材料学会

11

1021

1026

2006-11

In order to evaluate the strain rate dependence of the dynamic flow stress of 6061-T6 aluminum alloy, strain rate reduction tests are conducted in the strain rate range from about 2×10^4 to 4×10^4s^<-1>, which is the strain rate range before reduction, and the reduction in strain rate is 58.6%. To eliminate an effect of elastic wave dispersion produced in a bar on the measured flow stress, a output bar being 2mm in diameter is employed. A steep increase in the flow stress was observed at the strain rate of about 2×10^4s^<-1>. A simplified model for dislocation kinetics under dynamic plastic deformation is used which can represent a transition in the rate controlling mechanism of dislocation motion from a thermally activated process to a viscous drag. It is comfirmed that the steep increase in the flow stress of 6061-T6 observed at the strain rate of about 2×10^4s^<-1> is attributed to the rate dependence of the viscous drag on the dislocation motion and furthermore, the increase in the mobile dislocation density lowers a velocity of moving dislocations and shifts the transition region, or the strain rates in which the steep increase in the flow stress becomes to appear, to the higher strain rate side.

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