3D printing AISI 316L History of engineering & technology LPBF Ni–Cu alloy additive manufacturing amorphous poly(lactide acid) as-built as-cast ceramics design of experiments directed energy deposition filament extrusion fused filament modelling fused-deposition modeling high performance ceramics lithography-based ceramic manufacturing materials development mechanical properties metals microhardness microstructure photopolymerisation poly(styrene-co-methyl methacrylate) polyetherimide polymer blends polymers silicon nitride tensile test thermal behavior