its an experiment, the cucl2 slightly dissolved in water al was put then it accumulated rust..?

Answer 1

That is not rust! This solid copper metal. You performed redox reaction where electrons were transferred from Al to Cu+2 forming Cu and Al+3. Some of Al dissolved in process.

Answer 2

What you saw was not rust, although it looks like rust. It was elemental copper, which was displaced from the solution by the aluminum, some of which dissolved.
Al + CuCl2 -> AlCl3 + Cu. I have not bothered to balance the reaction; you can do so if you want.

Answer 3

Its Copper

Answer 4

what???