Selective laser sintering of composite copper–tin powders

Selective laser sintering (SLS) is a rapidly developing additive manufacturing technique, with advantages in flexibility and low material waste. Many parameters used in a SLS process are determined by powder type: blended powders have limitations due to wetting and diffusion, while prealloyed powders require processing in a small temperature range dictated by the alloy composition. As an alternative to these, a coated powder was fabricated by electrochemical means. This tin–copper composite powder was compared with a blend of tin and copper powders, using metallographic, crystallographic, and thermal analysis techniques as well as SLS. It was found that, because of the uniform distribution of liquid and increased contact between phases in the composite powder, sintering took place in the composite powder but not in the blend. After a homogenization treatment, mechanical testing of the sintered samples showed that the strength and ductility were comparable to high-porosity materials produced using other techniques.