Why is the mixture of metals in Figure 2 harder than the pure metal?

Answer 1

The mixture of metals in Figure 2 is harder than the pure metal because it forms an alloy. The presence of another metal or metals in a pure metal can disrupt the orderly arrangement of atoms in the lattice structure of the pure metal. This disruption creates a barrier that makes it more difficult for the atoms to slide past each other when the alloy is deformed or stressed, thereby increasing its hardness. Additionally, some metals may have different crystal structures or atomic sizes, which can also contribute to strengthening the alloy and making it harder than the pure metal.