A locking device providing thermal management for an electrical assembly board is described and includes a fluid-permeable member saturated with a fluid and disposed between the electrical assembly board and a heat sink; a pair of locking device substrates substantially orthogonal to the electrical assembly board and the heat sink; and an actuator coupled to at least one of the locking device substrates. The fluid-permeable member is disposed between the locking device substrates. The actuator is configured to compress the fluid-permeable member by at least one of the locking device substrates forcing a portion of the fluid out of the fluid-permeable member and forming at least one fluid contact interface with the electrical assembly board and the heat sink in a reversible process. A method for making a locking device is also described.