Selective laser remelting of an additively manufactured Cu-Al-Ni-Mn shape-memory alloy

Abstract

Selective laser melting (SLM) was used to manufacture fully martensitic (β′1) samples of the shape-memory alloy 81.95Cu-11.85Al-3.2Ni-3Mn (wt%). Crack-free specimens with a high relative density of about 98.9 ± 0.1% were produced. Immediate remelting of already processed layers during SLM enhances the relative density (99.5 ± 0.3%). Primarily by varying the scanning speed in the remelting step, the thickness of the remelted zone can be adjusted. Moreover, remelting alters the microstructure as well as the transformation temperatures, which tend to rise with the volumetric energy input. In this way, the shape-memory properties can be modified without compromising the relative density and the considerable plasticity of the samples. Thus, the remelting procedure proves to be an interesting tool for 81.95Cu-11.85Al-3.2Ni-3Mn and related alloys in order to optimize and tailor their performance already during SLM processing and without applying additional post-processing steps.