Why are the metals aluminium and titanium so usefull?
Their main benefit is their corrosion resistance.especially in oxidising atmospheres and another big benefit is they both have a high strength to weight ratio which is more important than their extra cost.Aluminium is extra useful because ,when unalloyed,it is very ductile and can be rolled into very thin foil and extruded into food and drinks cans with very thin walls.The same is not true of titanium which is essentially a brittle metal in the commercially pure form.
