Temperature dependence of the flow stress of III-V compounds

An interpretation for the temperature dependence of the plastic flow stress of III-V compounds is presented, invoking only non-dissociated screw dislo cations. With the aid of the Stillinger-Weber potential for the interatomic interaction, the Peierls potential of a non-dissociated screw dislocation is deduced in two-dimensional space normal to the dislocation line. A saddl e-point configuration and the formation energy of a kink pair are calculate d in three-dimensional space. The relation obtained between the flow stress tau (c) and temperature T under a constant strain rate describes the exper imental tau (c)-T relation of III-V compound well: a strong T dependence at high tau (c) and low T, a stronger T dependence at low tau (c) and high T, and a plateau-like tau (c) at intermediate T. The hump in the tau (c)-T re lation is interpreted as a transition between different paths of the non-di ssociated screw dislocation; a planar path and a zigzag path in the(111) pl ane.