“…Powders of Ni 59 Zr 15 Ti 13 Si 3 Sn 2 Nb 7 Al, [ 121 ] Fe 75 Nb 3 Si 13 B 9 , [ 122 ] Cu 46 Zr 42 Al 7 Y 5 , [ 123 ] Zr 55 Cu 30 Al 10 Ni 5 , [ 124 ] Zr 70 Cu 24 Al 4 Nb 2 , [ 125 ] Ti 45 Zr 10 Cu 31 Pd 10 Sn 4 , [ 126 ] Mg 65 Cu 25 Gd 10 , [ 127 ] Hf 55 Cu 28 Ni 5 Al 12 , [ 128 ] and ZrCu 39.85 Y 2.37 Al 1.8 , [ 129 ] among many others, have also been prepared using the SPS technique with varying degrees of success, always optimizing for a temperature between the glass transition and crystallization temperatures, where the powders exhibit lower viscosity. Indeed, the viscosity of the specimens is relevant at all temperatures and impacts sample contraction during the beginning stages of densification by [ 130 ] where is the change in axial length of the specimen based on ram displacement, γ is the surface energy of the powders, R is the gas constant, T is the temperature, D is the average particle diameter, c is the heating rate, Q is the activation energy for viscous flow, and η o is the pre‐exponential constant in…”