What years were clad coins minted?

US clad coinage began in 1965.

Since then all dimes and quarters have been made of a pure copper core with outer layers of 25% nickel and 75% copper.

Halves were made of clad silver (80% copper/20% silver core, and the opposite on the outside) from 1965 to 1970. In 1971 the half dollar was changed to the same composition as dimes and quarters.

Eisenhower and SBA dollars are also made of the same copper-nickel clad metal.

Sacajawea and Presidential dollars are made of copper clad with layers of manganese brass.

Regardless of popular misunderstandings, nickels have never been made of clad metal, and since 1982 cents have been made of plated (but not clad) zinc.