Development of high strength aluminium alloys leveraging rapid solidification during laser powder bed fusion

摘要: The unique thermo-kinetic characteristics of laser-powder bed fusion (L-PBF) can be exploited for development of high strength Al alloys. There is an increasing trend to move away from conventional alloys used for traditional manufacturing processes like casting and forging to innovative alloys in L-PBF [1]. This talk will review ongoing research on development of new aluminium alloys with transition metals (Fe, Cr, Si, Ti, Zr, etc.) having low diffusion coefficients in the aluminium lattice, which are proposed as heat-resistant alloys which can be processed by L-PBF [2]. AlFeCrX (X=Si, Ti, Zr, etc.) metal powders have been fabricated via gas atomization and their characteristics such as morphology, composition and intermetallic phases have been evaluated. In addition, characterization of the melt pool shape has been considered in order to optimize the printing process parameters, such as laser power and scan speed, and avoid defects in the new developed compositions. Using the optimized LPBF parameters, highly dense (~99.8%) samples have been fabricated. Nevertheless, the microstructures and mechanical properties obtained depended strongly on the composition and the input energy densities due to the combinations of laser processing parameters.