Additive manufacturing (AM), known as 3D printing, enables rapid fabrication of geometrically complex copper (Cu) components for electrical conduction and heat management applications. However, pure Cu or Cu alloys produced by 3D printing often suffer from either low strength or low conductivity at room and elevated temperatures. Here, we demonstrate a design strategy for 3D printing of high strength, high conductivity Cu by uniformly dispersing a minor portion of lanthanum hexaboride (LaB₆) nanoparticles in pure Cu through laser powder bed fusion (L-PBF). We show that trace additions of LaB₆ to pure Cu results in an improved L-PBF processability, an enhanced strength, an improved thermal stability, all whilst maintaining a high conductivity. The presented strategy could expand the applicability of 3D printed Cu components to more demanding conditions where high strength, high conductivity and thermal stability are required.

Despite strong interest from many industrial sectors driving demand and advancements in laser additive manufacturing (LAM) of steels, some issues remain as barriers limiting the current industrial applications, such as defects, residual stress, scattered, inadequate or/and anisotropic properties. To overcome these problems, several effective approaches have been developed to control and/or enhance the properties of LAM produced steel components. To help researchers and engineers attain up-to-date information and knowledge in this rapidly growing area, the present work provides an overview of current research in LAM of steels, in particular austenitic steels, ferritic steels, duplex steels and martensitic steels, with a focus on understanding the interrelation between process, microstructure and mechanical properties. This review also includes substantive discussions on the effects of processing parameters, their interactions and post-LAM treatments on the metallurgy, microstructure and properties. In addition, the advances, ongoing challenges and outlooks in LAM of steels are highlighted.

Additive manufacturing (AM) creates digitally designed parts by successive addition of material. However, owing to intrinsic thermal cycling, metallic parts produced by AM almost inevitably suffer from spatially dependent heterogeneities in phases and mechanical properties, which may cause unpredictable service failures. Here, we demonstrate a synergistic alloy design approach to overcome this issue in titanium alloys manufactured by laser powder bed fusion. The key to our approach is in-situ alloying of Ti−6Al−4V (in weight per cent) with combined additions of pure titanium powders and iron oxide (Fe₂O₃) nanoparticles. This not only enables in-situ elimination of phase heterogeneity through diluting V concentration whilst introducing small amounts of Fe, but also compensates for the strength loss via oxygen solute strengthening. Our alloys achieve spatially uniform microstructures and mechanical properties which are superior to those of Ti−6Al−4V. This study may help to guide the design of other alloys, which not only overcomes the challenge inherent to the AM processes, but also takes advantage of the alloy design opportunities offered by AM.