Manufacturing metal parts via indirect SLS of composite elemental powders

Many more attempts have been made to develop new powder materials to fabricate metal objects via indirect SLS process. Unfortunately, current attention still focuses on singular alloy powders, which has confined the development of indirect SLS. Hence composite elemental powders (CEPS) of Fe–Cu–C system and Fe–Cu–Ni–C system are selected and obtained by briefly blending iron, copper, nickel, graphite and polymer binder powders in this study. Green shapes composed of aforementioned polymer bonded CEPS were formed via indirect SLS process firstly. Then full density hybrid alloys composed of Fe–Cu–C or Fe–Cu–Ni–C system alloys and copper were manufactured after the green shapes had been decomposed at 900 °C, sintered at 1200 °C, infiltrated at 1200 °C with molten copper and thermally treated. Some aspects of the SLS forming process and post process were discussed. The microstructures and the mechanical properties of sample alloys were investigated either. The bending strength of metal green shapes is 2.41 MPa; the binder material decomposes almost entirely below 900 °C; copper, nickel and graphite can diffuse into γ-Fe and distribute uniformly after sintering and infiltration process; quenched at different temperatures over 900 °C and tempered at 200 °C, the copper infiltrated alloys have a yield strength over 400 MPa and a elongation under 3%; compared to that of other alloys, the mechanical properties of hybrid alloy composed of Fe–8Cu–4Ni–0.5C alloy and copper are better. Hence CEPS can be used to manufacture metal parts via indirect SLS process, which is also an additional contribution to SLS.