Material Witness: V20N3
By David Lake
Second only to steel, aluminum is one of the most common metals used in construction, architecture, and general industry. The metal was first extracted from its ore in the first quarter of the 19th Century. 70 years would pass before aluminum alloy became economical enough to exploit its tremendous qualities of high strength and low weight. In its pure form, aluminum is soft and ductile- of little to no use as a structural material. It is highly reactive- that is, it easily interacts with and forms bonds with other materials. For this reason it is never found in nature in its pure form. Most commonly, aluminum ore presents as an oxide or silicate. In fact, aluminum is the most prevalent metal in the Earth’s crust. Aluminum can be recycled and repurposed indefinitely. If it can be said that the modern world is built on Steel- it must be said that the world moves forward on aluminum.
Everything that can be made of steel can be made of aluminum- by all modern standards and methods of manufacture and engineering. Aluminum can be formed and machined and otherwise worked as any other ductile metal can. The newest aluminum alloys claim a higher tensile strength than steel. There is even one particular type of aluminum that can best 6AL-4V titanium in most criteria- strength, weight, cost, and machinability. With all its boasting, Aluminum does fall short of other materials in some capacities. For starters, aluminum cannot offer the same resistance to heat as steel. High temp aluminum alloys exist, but they cannot approach steel’s 2500 degree melting temp. Aluminum enjoys only a relatively narrow temperature threshold where its strength and resilience remain useful (at the extremes of cold and hot, it becomes brittle and weak). And aluminum cannot endure the levels of abuse and mechanical stress that steel may take in stride. Aluminum tends to be slightly less forgiving than steel when pushed close to its limits of operational loads. It is indeed very strong per given mass- stronger than the same mass of steel. But while steel is tends...
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