A shield assembly is employed for a friction brake used to decelerate a road wheel of a vehicle. The vehicle has a body with a first body end configured to face an incident ambient airflow, a second body end opposite of the first body end, and an underbody section spanning a distance between the first and second ends. The shield assembly includes a first shield component arranged proximate the brake and rotationally fixed relative to the vehicle body. The shield assembly also includes a second shield component operatively connected to the first shield component for shifting relative thereto. The shield assembly additionally includes an actuator employing a shape memory alloy element to shift the second shield component relative to the first shield component in response to a temperature of the brake to thereby direct at least a portion of the airflow to the brake and control temperature thereof.