During recent years, there has been a growing interest in copper-based materials for structural high-heat-flux applications. This results from two significant developments: the advancement of additive manufacturing (AM) and the positive impact of space exploration. In line with this context, the present work focuses on characterizing a new copper-based material developed via laser powder bed fusion (LPBF). The Italian company SÒPHIA HIGH TECH S.R.L. has patented a powder mixing system known as POWMIX. Using this technology and starting from a powder mixture of 80% pure copper and 20% 17-4PH martensitic stainless steel, it was possible to produce a multiphase material through in situ alloying with LPBF .