A thermally releasable fastening element, in particular for fastening a door actuator, includes a base body, which is designed to be inserted into a recess or a number of aligned recesses, a core inserted into the base body, at least partially made of a shape memory material, wherein the base body has an unstable area, which is stabilized by the core, and wherein the core is designed to withdraw at least partially from the unstable area upon thermal activation of the shape memory material.

An apparatus for holding and releasing a pin in a controlled manner comprises a base, a pin holding element supported at the base, a plurality of rod-shaped release elements made of a shape memory alloy and supported at the base, a holding force application device supported at the base for applying an elastic holding force, and a force transfer element. The force transfer element is subjected to the elastic holding force and, against the elastic holding force, supported at the base via a parallel arrangement of the pin holding element and the release elements. The release elements are arranged with radial play in blind holes in the base, which are arranged around the pin holding element. The pin holding element is deactivatable by heating up the release elements beyond a transition temperature of their shape memory alloy and by a resulting recovery of the release elements to straight memory shapes.

An anchor including shape memory metals, shape memory polymers or a combination thereof. The anchor has surgical and nonsurgical uses.