Like liquid stone frothed inside a volcano, we should be able to create the conditions to produce foamed metal alloys. Process aeration, with the goal of material conservation, weight reduction, added strength, and consistent formability.
Metal taken to liquid form in a pressurized furnace. The liquid may be combined with other thinner metals that serve as a conditioner, to encourage smoothness and bubbles. Also minerals that react, to generate more air infiltration. calcium, carbon. the mixture may be whipped until many persistent bubbles form.
the mass of foaming metal can then be extruded, rolled out or placed into molds where the pressure is maintained and bubbles are stable. this would cool slowly to keep the microstructures intact.
Specialized facilities would be required for this process. Extreme mixing and curing furnaces, with implements that could easily withstand temperatures of the liquified metals.
foamed ceramic produced a similar way may be components included.