Cryogenics take a step of heat treatment to the extreme. When we start to heat treat an aluminum alloy, it is usually annealed, or in the O condition. This is when the material is the most ductile for forming. Most structural alloys will work harden as you are forming, and complex parts can build up enough work hardening that the part has to be re-annealed several times during the forming process to relieve the internal stresses being developed by the cold working process. We done this 4 times making the door frame for the Constellation by hand. We debated a hot hydroform process, but the cost was triple what it was to pound a couple out by hand.
So, once you have your desired final form, and all thermal modification is complete, to include any welding involved, it is time to Solution heat treat, if you did not weld. If you DID weld, the craftsman's trick of the trade is to re-anneal the entire assembly one more time prior to solution heat treat.
Solution heat treatment gets it's name from the Greek solidus. Solidus is the solid matter state of the alloy, followed at rising temperature by liquidus, the point that the metal will pour or collapse from vertical form. In solution heat treatment, we elevate the alloy to a point 40-60 percent into the range of temperature BETWEEN solidus and liquidus, and get all the molecules moving at the same speed and in uniform direction. Any compression of the molecules is relieved, and any stretched areas or thinning of the molecular bond is filled, and everything has homogenous properties. This state is preserved by quenching the part quickly in cool water. The molecules stop "flowing" and are in a semi-bonded state. The part "ages" over the next 72 hours to develop the final strength properties we use for calculations. This is called a natural age hardening, where the passage of time at normal range atmospheric temperatures is all that is used. In artificial age hardening, we can take that part, after it is naturally age hardened to it's intermediate temper, and elevate it's temperature once again, but only into the 240-280 degree range, depending on which process is specified, or develops the specific characteristic we are going for the best. The part is raised to the specific temperature for anywhere from 8 to 40 hours, then cooled by removing from the oven. In working with a few folks that know WHAY more than I do (they came from the F35/F22 program), I've been told of proprietary processes that do liquid nitrogen bath cryogenic treatment to annealed materials (to stabilize grain boundaries and stress relieve highly stressed stretch and compression points) intermediate heat treated materials (to accelerate the development of the intermediate properties for maufacturing purposes) and to the advanced age hardened or over-aged conditions of some of the newer unobtainium (7150, 7165) to modify corrosion resistance or after a shot peening treatment on certain of these high grade alloys (supposedly aids in homogenizing the effects of the shot peening)
In the end, non-ferrus metal work (whitesmithing) is no less technical and no less a trade than blacksmithing, you have a significant amount of information to apply to your craft that has nothing to do with pounding out pretty parts on a shot bag and an English wheel, if you expect your product to endure the test of time. A poor heat treat condition for the intended use results in failure. Either high cycle fatigue in the case of high stress attachment or uneven heat treat, or not enough strength in the material to support the in-service loads without bearing or compression failure. This is what engineers are supposed to figure out on paper (or screen, nowadays) for you before you make the first lick. If not, lessons can be hard, and expensive.
If I were experimenting with heat treatment or cryogenic treatment, I know enough to know it would be useless without a rigorously controlled and repeatable test protocol to validate the increase or decrease in strength, durability, ductility, or corrosion resistance.
Attached is a pic of the cast block we made to beat out the double zee cross section of the secondary cockpit door in a single homogenous piece. We made 3, just in case. A one-off forming job is NEVER just one, if you are smart.