We investigate grain boundary (GB) melting using molecular dynamics simulations on face-centeredcubic Cu bicrystals with symmetric /1 1 0S tilt GBs. Two representative types of GBs are explored: S ΒΌ 11=Γ°113Γ=50:48 3 (low GB energy) and S ΒΌ 27=Γ°552Γ=148:41 3 (high GB energy). The temperature and temporal evolutions of the Cu bicrystals under stepped heating are characterized in terms of order parameters and diffusion coefficients, as well as the nucleation and growth of melt. Within the GB region, continuous local melting precedes discontinuous bulk melting, while continuous solid state disordering may precede local melting. Premelting may occur for local melting but not for bulk melting.
For S ΒΌ 11=Γ°113Γ=50:48 3 , premelting of the GB region is negligible, and local melting occurs near the thermodynamic melting temperature. The GB region as a whole is superheated by about 13% before its bulk melting. In the case of S ΒΌ 27=Γ°552Γ=148:41 3 , considerable premelting is observed for local melting, while the bulk melting occurs with negligible superheating. The exact melting behavior of a general GB depends on the GB energy, but is likely bracketed within these two cases.