Powder preparation during ball milling and laser additive manufacturing of aluminum matrix nanocomposites: Powder properties, processability and mechanical property

Abstract

• Nanocomposite powder for additive manufacturing was economically prepared. • The nanocomposite powder showed near-spherical shape and high flowability. • Nano-TiB 2 particles was uniformly dispersed on the surface of aluminum powder. • The optimal nanocomposite powder exhibited good processability. • The as-fabricated nanocomposite exhibited favorable mechanical property. The additive manufacturing method of laser powder bed fusion (LPBF) has a great potential in producing high-performance metal matrix nanocomposite components. However, nanocomposite powder feasible for LPBF is still limited in availability. In this work, AlSi10Mg powder containing 2 wt% TiB 2 nanoparticles was prepared by ball milling of the constituent powder to meet the following two criteria: (i) a uniform dispersion of nanoparticles on the surface of the micro powder and (ii) a high flowability of the produced nanocomposite powder. The evolution of the powder properties with the milling dose was studied. The results indicated that with the increase of milling dose, the nano-TiB 2 particles were dispersed uniformly but the Al matrix gradually underwent plastic deformation. Under optimized milling conditions, the aluminum matrix nanocomposite powder showed a small mean particle size, narrow size distribution, smooth surface, and a spherical shape with uniformly dispersed nanoparticles. These properties are beneficial for a good LPBF processability. During LPBF process, a favorable forming quality of the optimized nanocomposite powder was evident. A mechanical characterization demonstrated an outstanding tensile strength of ∼ 450 MPa and excellent ductility of ∼ 7.2 % for the built parts.