A biodegradable composite material or device including at least one biodegradable polymer matrix material and at least one filler component. The material or device has an initial shape and at least one evolved shape. The evolved shape is different from the initial shape. The initial shape is adapted to change towards the evolved shape. The filler component is adapted to accelerate and/or amplify the transformation from the initial shape towards the evolved shape when the external stimulus for transformation is given by physiological conditions. Also a method to control the shape transformation rate of a composite material or device.