Borg vessels are constructed enitrely out of this SMA tritanium including all internal components and technology. After being deformed/damaged by weapons fire, asteroids or by any other means a forcefield is erected encompassing the damaged area both inside and outside of the vessel, allowing the area inside to be heated in the freezing dead of space. The mineral is then heated to such extreme temperatures by the billions of external conduits around the exterior of the Borg vessel causing it to re-align to its intended configuration. Following their re-alignment the forcefield is deactivated causing the mineral to quickly re-cool. Following this nanoprobes are then distributed by the automated regeneration matrix around the damaged area allowing for microscopic imperfections and residual flaws resulting from the damage to be repaired and the hull layers to be merged together once again.
The entire process consumes such tremendous amounts of power to heat up the external hull armour to such extreme temperatures in the absolute zero temperature of space in such a short period of time, This is the reason why smaller Borg vessels such as a Sphere are required to power down several other ship systems entirely while regenerating . For this reason, regeneration is not always possible and a significant number of Borg drones must enter their regeneration alcoves in order to siphon their own power in-to the vessels power systems, increasing the vessels power output and thus increasing the speed of regeneration.
One-Way Memory Effect - Wikipedia
When a shape memory alloy is in its cold state (below As), the metal can be bent or stretched and will hold those shapes until heated above the transition temperature. Upon heating, the shape changes to its original. When the metal cools again it will remain in the hot shape, until deformed again.
With the one-way effect, cooling from high temperatures does not cause a macroscopic shape change. A deformation is necessary to create the low-temperature shape. On heating, transformation starts at As and is completed at Af (typically 2 to 20 °C or hotter, depending on the alloy or the loading conditions). As is determined by the alloy type and composition. It can be varied between −150 °C and 200 °C.
The reason other races such: Starfleet has not been able to repoduce this technology is down to far too limited resources for such extensive external conduits, absence of sufficient scientific understanding to convert manipulate tritanium's crystlline structure in-to a shape memory alloy and the process is all far too costly for Starfleets limited warp core technology which does not produce sufficient power to accomodate this technology.