Because aluminium is not only cheaper but lighter. - Dave! Yognaut
Airplanes are made out of an alloy of aluminum and brass called "duraluminium."
Depending on the rocket it could be made of an aluminium alloy, a steel alloy or titanium.
Aluminium and steel.
Either steel, an iron-based alloy, or some sort of aluminium-based alloy.
Aluminium, steel and many plastics and composite materials.
duralumin, copper is added to the aliminium to make duralumin
In several places actually. Fasteners - screws, nuts and bolts - are usually steel. Wheel axles, freewheel mechanisms, brake parts tend to be steel. Aluminium forks may have steel steerers. Bearings tends to use steel.
Mostly aluminium alloys, but some aircraft have used steel, titanium and more recently, composite materials.
Generally motorcycle blocks are made of either cast Iron, or Cast Aluminium. A lot of custom metals are available for the highest end race teams, but odds are if you run into a modern dirt bike, the block will be cast aluminium, the pistons will be a steel alloy, the crank will be either cast iron or a steel alloy, and the Connecting rods (between the pistons and the crank) will be either a steel alloy, or an aluminium alloy. Possibly titanium in various percentages in any or all components. Older engines will be generally the same, but the block will be more than likely made of cast iron.
Not so good compared to metals such as copper and aluminium. Steel is an alloy where as copper is a pure metal
An alloy of Magnesium is a type of steel with Magnesium as the main ingredient. For example, Magnox is 99% Magnesium and 1% Aluminium is a steel used for the cladding of fuel rods in some nuclear power stations. Another alloys with Magnesium contain Aluminium, Zirconium, Silver, Zinc, and the Rare Earth Elements such as Yttrium and Erbium.
Usually different metals. Aluminium alloy hub and rim, stainless steel spokes and steel axle and bearings. But there can be steel rims and steel hub bodies too, as well as carbon fiber rims and carbon fiber hubs. Carbon fiber or aluminium spokes does happen, but is rare.