Machine for Producing Square Torsion Pulses of Microsecond Duration

Abstract

A dynamic torsion testing machine has been built for the purpose of applying a known constant shear stress to a 12.7‐mm‐diam cylindrical test specimen for very short periods of time. The shear stress at the surface of the specimen rises from zero to any desired value in the range 0 to 3000 psi, within a period of 4 to 6 μsec. The time at constant stress varies linearly with axial position from the free end of the specimen ranging from 0 to about 500 μsec. The stress is removed within a period of 4 to 6 μsec and for short specimens it remains essentially zero thereafter. This machine has been developed for the measurement of dislocation velocities up to 25 m/sec in metal single crystals.