S0404-1-1 ニオブの高ひずみ速度域における変形機構(衝撃問題の新たなる展開と応用(1))

Abstract

Constant strain rate tests are made on niobium in the strain rate range from about 4×10^3 to 3×10^4/sec at temperatures of 293K, 423K and 573K. At high strain rates, decremental strain rate tests are also performed. The flow stress depends on a instantaneous strain rate and the strain rate dependence of the flow stress is the almost same as that obtained from the high strain rate tests on iron. A thermally activated process is employed to evaluate the strain rate dependence of the dynamic flow stress at high strain rates. The deformation mechanism is a dislocation motion which surmounts the Peierls potential barriers with a aid of the thermally activated process of a formation of kink pairs.