A vaso-occlusive device delivery assembly includes a pusher assembly and a vaso-occlusive device detachably coupled to the pusher assembly by an attachment member is frictionally secured within a lumen of the pusher assembly. A heat generating member is disposed in the pusher assembly lumen, along with a pressure generating material, such that, when heat is generated by the heat generative device, the pressure generating material increases a pressure in the pusher assembly lumen, thereby dislodging the attachment member from the pusher assembly and detaching the vaso-occlusive device from the pusher assembly.