Residual stress distribution in Cu-4.3%Sn alloys fabricated by selective laser melting (SLM)

This paper is focused on the investigations of the residual stresses present in SLM Cu-4.3%Sn alloys, which were fabricated by the SLM process. The source Cu-4.3%Sn powder was analyzed for basic characteristics, and then the residual stress state was determined for 3D printed samples with different geometries before and after heat treatments. Stress measurements were performed using the X-ray diffraction ꞷ-sin2ψ method. Nonhomogeneous residual stresses were found to be present within SLM Cu-4.3%Sn alloys samples. Biaxial tensile stress was revealed in the interior of as-printed cube samples and it was reduced by annealing, whereas thin strip samples contained biaxial compressive stresses and after annealing the stress became more equi-biaxial but it was not reduced to zero near the sample surface. The results suggest how residual stresses are distributed within the copper SLM alloys with a simple shape. More complex geometries are expected to have correspondingly more complicated stress states. The performed investigation provides insight in to the residual stress distribution in copper alloys fabricated via SLM, which have not been widely studied yet. Application of the ꞷ-sin2ψ technique to the SLM process was analyzed and it was found that the methodology of utilizing the ꞷ-sin2ψ can be widely applied using standard X-ray diffraction facilities to study residual stresses within the additively manufactured metal alloy parts.

---

Celem pracy było ustalenie stanu naprężeń własnych w stopach Cu-4,3%Sn wytwarzanych metodą selektywnego stapiania laserowego (SLM). Wyniki pomiaru naprężeń zostały skorelowane z uprzednio zmierzonymi właściwościami mechanicznymi i mikrostrukturą. W ramach pracy oceniono, czy zastosowany proszek ze stopu Cu-4,3%Sn spełnia oczekiwania stawiane materiałom na wyroby uzyskiwane techniką SLM oraz sprawdzono, czy metoda dyfrakcyjna ꞷ-sin2ψ jest odpowiednią metodą do pomiarów naprężeń szczątkowych w wyrobach ze stopu miedzi wykonanych metodą SLM.

---

Opracowanie rekordu ze środków MNiSW, umowa Nr 461252 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2020).