Rolled or extrudet aluminum has much better mechanical characteristics than cast aluminum: several times higher strength, uniformity of properties in cross section and length, shape accuracy, absence of pores and other typical casting defects. Without pressure treatment it is impossible to obtain such high quality. In addition, aluminum is excellently deformed both hot and cold, which makes this forming cost-effective.

While extruding aluminium we apply compressive force which reduces particle to particle distance hence increases its tensile strength.Secondly extrusion creates smooth structures which also reduces human effort.As an engineer we should look towards easy way which is economical by reducing machining as well as time.No doubt through casting we can create strong aluminium part but requires more time for machining along with die cost.Energy cost for melting and sometimes design is so complex that to get smooth structure working time increases

I have heard, since at least 2009, of major deposits of Aluminum being found, in Africa(?), and thus industry needing research to find new uses of Aluminum. Whereas I always guffawed at the audacity of Steve Jobs then implementing a solid-state-Aluminum laptop case in response to sharp drops in the Aluminum market, I do think that was a consumer-successful use of Aluminum. However, what about just keeping the Aluminum in an "Aluminum savings account" (aka, unmined)... Just because we suddenly found a lot more Aluminum deposits does NOT mean we need to mine and capitalize on them. That is just the Native American way of thinking from my culture, though... Try making a case, Jack Don McLovin

I didn't understand the entirity of your question before, Jack Don McLovin

Further Context, like it is a fictional spy novel I am writing called: "Three Princes": Selling American Aluminum reserves was an occurance of the early Obama era and Steve Jobs was consulted with and committed Apple to a major purchase that would justify the profitability of selling major American stockpile of Aluminum reserves held in other countries of the world. A plus was that the Aluminum could be shipped direct to factories in Asia and did not have to enter and re-export with costly associated tarrifs. What the self-off of American interest in African aluminum mines did was open up the market for speculation in African aluminum mining which, in turn, drove up the speculative market of R&D for aluminum smelting. For years after, every man I met, seemed to eventually take up the useful utilitarian hobbies of "solving plumbing problems", "figuring out when something could be both wrong and right", and "smelting aluminum". There were others. It was like the pop-culture equivalent of the Millenium problems (which were summarily solved long ago).