Shock-induced phase transformation in tantalum.

A TEM study of pure tantalum and tantalum-tungsten alloys explosively shocked at a peak pressure of 30 GPa is presented. While no omega phase was found in shock-recovered pure Ta and Ta-5W which mainly contain a cellular dislocation structure, a shock-induced omega phase was found in Ta-10W which contains evenly distributed dislocations with a density higher than 1 × 10(12) cm( - 2). The shock-induced [Formula: see text] (hexagonal) transition occurs when the dynamic recovery of dislocations becomes largely suppressed in Ta-10W shocked under dynamic-pressure conditions. A dislocation-based mechanism is proposed for the shock-induced phase transformation.