Abstract: A piezoelectric actuator and a method of assembling and employing a piezoelectric actuator. This method comprises the steps of positioning an expandable piezoelectric material inside a case, and enclosing a vaporizable liquid in the case. The case is positioned in a high temperature environment; and the liquid vaporizes, in that high temperature environment, over a given period of time, to maintain the temperature of the piezoelectric material below a given value for said period of time. Preferably, the vaporizing liquid maintains the temperature of the piezoelectric material substantially constant over that period of time. Also, preferably the case is provided with a pressure responsive valve that opens and closes, in the high temperature environment, to expose the liquid to that environment and control the vaporization of the liquid to maintain the temperature of the piezoelectric material substantially constant over the period of time.