Pin fin heat sink with integrated phase change material and method

A pin fin heat sink comprising:

• a plurality of pin fins extending from a base plate, at least one of the plurality of pin fins defining a hollow portion therein, wherein all of the pin fins have different diameters relative to each other and at least one of the pin fins has a length different from one of the other fin pins;
• a phase change material sealed within the at least one pin fin to absorb transient thermal loads that the pin fin is subjected to;
• and
• a metal foam material disposed within the hollow portion, the metal foam material positioned along a central portion of the hollow portion to define an annular space between the metal foam material and an inner wall of the pin fin.