The problem of the maximum oscillation frequency of composite bimetallic microactuators excited by thermal pulses has been theoretically investigated. Both traditional bimetallic composites made of metals and alloys with different coefficients of thermal expansion and composites in which one of the layers is made of a mechanically pre-stressed shape memory alloy (SMA) and the other of a reliable elastic metal are considered. Two modes of thermal excitation of vibrations of bimetallic microactuators have been studied: excitation of forced vibrations using thermal rectangular pulses with a duty cycle of 0.5, as well as excitation of resonance vibrations of a bimetallic actuator by short pulses with a high duty cycle. The characteristics of the modes of free and forced mechanical vibrations of a composite bimetallic microactuator are presented. The optimal duration of the thermal pulse for the excitation of free mechanical vibrations of the actuator has been determined. The maximum frequency of forced mechanical vibrations of a composite actuator having different lengths and made of different materials is calculated. The prospects of using high-speed bimetallic microactuators for the creation of mechanical nanotools designed for nanoassembly and processing of individual nanoobjects such as carbon nanotubes, nanowires, etc. are considered.