(color online) The morphology of helium nanobubble releasing near the nickel surface as a function of the simulation time at He-to-vacancy ratio 3:1 for Z[001] crystal orientation at 300 K. The red balls represent the nickel atoms and the blue balls represent the helium atoms. (a) 0.25 ps, (b) 1.00 ps, (c) 2.50 ps, (d) 7.50 ps, (e) 12.50 ps, (f) 15.00 ps, (g) 20.00 ps, (h) 25.00 ps, (i) 30.00 ps, (j) 40.00 ps, (k) 50.00 ps, and (l) 250.00 ps.