What materials do you want for bicycle frame and fork?
There is only one choice. Cheap bicycles (generally less than 10,000 RMB) are now made of aluminium alloy. Steel frames are much heavier than aluminium alloys, and only a few hundred cheap cars and some extreme bicycles still use steel frames.
Other common materials are: titanium alloy/magnesium-aluminum alloy/scandium alloy/carbon fiber.