Plug and method of unplugging a seat

1. A method of unplugging a seat, comprising:

dissolving at least a surface defined by a shell surrounding a core of a plug seated against the seat;

unseating the plug from the seat;

dimensioning the core to fit through the seat without dissolving the core; and

passing the core through the seat.

2. The method of unplugging a seat of claim 1 , wherein the dissolving includes corroding.

3. The method of unplugging a seat of claim 1 , wherein the plug is a ball.

4. The method of unplugging a seat of claim 1 , wherein the unseating includes unsealing.

5. The method of unplugging a seat of claim 1 , wherein the unseating includes dislodging.

6. A plug comprising a body having an outer surface defined by a shell surrounding a core configured to seatingly engage a seat, the shell being configured to dissolve upon exposure to a target environment, the core being dimensioned to allow passage of the core through the seat upon dissolution of the shell without dissolution of the core.

7. The plug of claim 6 , wherein dissolution of the shell unseats the plug from the seat.

8. The plug of claim 6 , wherein the dissolution occurs at a known rate.

9. The plug of claim 6 , wherein the dissolution occurs at a uniform rate.

10. The plug of claim 6 , wherein the plug is a ball.

11. The plug of claim 6 , wherein the target environment includes wellbore fluid.

12. The plug of claim 6 , wherein the target environment includes elevated temperatures.

13. The plug of claim 6 , wherein the target environment includes elevated pressures.

14. The plug of claim 6 , wherein the plug is supportive of fracturing pressures prior to dissolution of the shell.

15. A plug comprising a body having an outer surface configured to seatingly engage a seat, at least the outer surface of the body being configured to dissolve upon exposure to a target environment at least the outer surface of the body being made of a powder metal compact, comprising:

a substantially-continuous, cellular nanomatrix comprising a nanomatrix material;

a plurality of dispersed particles comprising a particle core material that comprises Mg, Al, Zn or Mn, or a combination thereof, dispersed in the cellular nanomatrix; and

a solid-state bond layer extending throughout the cellular nanomatrix between the dispersed particles.

16. The plug of claim 15 , wherein the dispersed particles comprise Mg—Zn, Mg—Zn, Mg—Al, Mg—Mn, Mg—Zn—Y, Mg—Al—Si or Mg—Al—Zn.

17. The plug of claim 15 , wherein the dispersed particles have an average particle size of about 5 μm to about 300 μm.

18. The plug of claim 15 , wherein the dispersed particles have an equiaxed particle shape.

19. The plug of claim 15 , wherein the nanomatrix material comprises Al, Zn, Mn, Mg, Mo, W, Cu, Fe, Si, Ca, Co, Ta, Re or Ni, or an oxide, carbide or nitride thereof, or a combination of any of the aforementioned materials, and wherein the nanomatrix material has a chemical composition and the particle core material has a chemical composition that is different than the chemical composition of the nanomatrix material.

20. The plug of claim 15 , wherein the cellular nanomatrix has an average thickness of about 50 nm to about 5000 nm.