How would changing the proportions of substances in an alloy change its properties

It would change is various properties like ductility, tensile strength, durability and hardness.

Explanation:

When the proportion of substance in the alloy  change there will be change in its physical properties.

The different substance which are add in alloys in definite proportional will change the properties of alloys and these properties are the toughness of the alloy will change, its ductility means the alloy can be converted into wires, its durability also change and also its tensile strength will alter.