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How did Alfred Wilm’s discovery of age hardening improve aluminum alloys?

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Diagram of a zinc-lead blast furnace system showing ore and coke entering through charge hoppers, with labeled furnace, air preheater, blower, taphole for slag and lead bullion, and a connected lead-splash condenser using rotors to separate and cool lead and zinc, with pathways for molten metals and off-gas. — metallurgy A zinc-lead blast furnace and lead-splash condenser. This technology is utilized mainly for producing zinc while managing both lead and zinc from raw materials, a technique that was highly influential in 20th-century smelting.

Alfred Wilm’s discovery of age hardening, made around 1906, revolutionized the use of aluminum by enabling the creation of alloys that were twice as strong as previous versions with only a negligible increase in weight.1

In Wilm’s process, alloying elements such as copper or magnesium are trapped in a supersaturated solid solution by quenching the metal from a high temperature rather than allowing it to cool slowly. While the resulting alloy is initially soft and ductile enough to be mechanically formed, it undergoes a hardening process when left at room temperature or heated at low temperatures.1

This phenomenon, known as precipitation hardening, occurs because the aging process causes the dispersion of very fine precipitates throughout the metal. These particles act as barriers that restrict the movement of dislocations within the crystalline matrix, which is the mechanism essential to crystal deformation. By inhibiting this movement, the process significantly increases the strength of the metal, leading to the development of high-strength materials like duralumin.123