Why are the properties of alloys gnerally superior to their constituent components?

In most cases, not all, mixing metals forms eutectics (sometimes called eutectic mixtures). These eutectic mixtures are the combination of the elements that form the lowest melting point of the system and as such they may have different chemical sturctures, different corrosion resistance, strength, etc. Here is a site that tells a little about eutectics. Scroll to near the end of the page where the article talks about the varying properties as a result of forming alloys.
http://en.wikipedia.org/wiki/Eutectic

Alloys are typically superior to their constituent components due to the formation of eutectic mixtures. When different metals are mixed together to form an alloy, they can combine in such a way that their properties are improved compared to the individual metals.

Eutectic mixtures are formed when the combination of metals results in the lowest melting point of the system. This means that the alloy has a lower melting point than its constituent metals, making it easier to work with and shape.

Additionally, eutectic mixtures can have different chemical structures compared to the individual metals. This can lead to differences in corrosion resistance, strength, hardness, and other properties. By manipulating the composition and proportions of the metals in an alloy, engineers and metallurgists can tailor these properties to meet specific requirements.

To learn more about eutectics and how they impact the properties of alloys, you can visit the following link:
http://en.wikipedia.org/wiki/Eutectic. Scroll to near the end of the page where the article talks about the varying properties as a result of forming alloys.