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Purpose: The metallic alloys and their components fabricated via laser powder bed fusion (LPBF) suffer from the microvoids formed inevitably due to the extreme solidification rate during fabrication, which are impossible to be removed by heat treatment. This paper aims to remove those microvoids in as-built AlSi10Mg alloys by hot forging and enhance their mechanical properties. Design/methodology/approach: AlSi10Mg samples were built using prealloyed powder with a set of optimized LPBF parameters, viz. 350 W of laser power, 1,170 mm/s of scan speed, 50 µm of layer thickness and 0.24 mm of hatch spacing. As-built samples were preheated to 430°C followed by immediate pressing with two different thickness reductions of 10% and 35%. The effect of hot forging on the microstructure was analyzed by means of X-ray diffraction, scanning electron microscopy, electron backscattered diffraction and transmission electron microscopy. Tensile tests were performed to reveal the effect of hot forging on the mechanical properties. Findings: By using hot forging, the large number of microvoids in both as-built and post heat-treated samples were mostly healed. Moreover, the Si particles were finer in forged condition (∼150 nm) compared with those in heat-treated condition (∼300 nm). Tensile tests showed that compared with heat treatment, the hot forging process could noticeably increase tensile strength at no expense of ductility. Consequently, the toughness (integration of tensile stress and strain) of forged alloy increased by ∼86% and ∼24% compared with as-built and heat-treated alloys, respectively. Originality/value: Hot forging can effectively remove the inevitable microvoids in metals fabricated via LPBF, which is beneficial to the mechanical properties. These findings are inspiring for the evolution of the LPBF technique to eliminate the microvoids and boost the mechanical properties of metals fabricated via LPBF. [ABSTRACT FROM AUTHOR]

The corrosion resistance of 5083 aluminum alloy after refining with nano-CeB 6 /Al inoculant was investigated by 3.5 wt% NaCl solution, compared with that of as-cast alloy and cold-rolled alloy. It was found that nano-CeB 6 /Al inoculant showed significant grain-refining effect on 5083 alloy and the corrosion resistance of 5083 Al alloy was improved as well. The results of potentiodynamic polarization tests showed that the polarization resistance of refined alloy was higher than that of as-cast alloy and cold-rolled alloy, together with more positive breakdown potential value. The corrosion rate was dependent on the grain size following a power law type relationship, which was attributed to the reduced precipitate on the grain boundary. Unlabelled Image • CeB 6 inoculant can effectively refine 5083 aluminum alloy and improve its corrosion resistance. • The corrosion rate was dependent on the grain size following a power law type relationship. • Refined intergranular precipitates reduce the pitting tendency of aluminum. [ABSTRACT FROM AUTHOR]

The mechanical properties of iron-rich Al–Si alloy is limited by the existence of plenty of the iron-rich phase (β-Al5FeSi), whose unfavorable morphology not only splits the matrix but also causes both stress concentration and interface mismatch with the Al matrix. The effect of the cooling rate on the tensile properties of Fe-rich Al–Si alloy was studied by the melt spinning method at different rotating speeds. At the traditional casting cooling rate of ~10 K/s, the size of the needle-like β-Al5FeSi phase is about 80 μm. In contrast, the size of the β-Al5FeSi phase is reduced to 500 nm and the morphology changes to a granular morphology with the high cooling rate of ~104 K/s. With the increase of the cooling rate, the morphology of the β-Al5FeSi phase is optimized, meanwhile the tensile properties of Fe-rich Al–Si alloy are greatly improved. The improved tensile properties of the Fe-rich Al-Si alloy is attributed to the combination of Fe-rich reinforced particles and the granular silicon phase provided by the high cooling rate of the melt spinning method. [ABSTRACT FROM AUTHOR]

An in situ TiC–TiB2/Al composite inoculant is prepared by melt spinning the sintered mixture of Al powder, Ti powder, B4C particles, and graphene nanoplates (GNPs). To increase the degree of dispersion of the particles, the GNPs are coated on the surface of the B4C particles by high‐energy ball milling before sintering. The as‐spun inoculant ribbons are added to the melt of a typical Al–Si alloy to verify its effect of refining the grains on aluminum alloys. It is found that the columnar grains of the as‐cast Al–Si alloy sample are refined to finely approximate equiaxed grains, with an addition level of 0.6 wt% of the inoculant ribbons. The mechanical properties of the as‐inoculated Al–Si alloys also improve significantly, and show a remarkable strengthening and toughening effect. It can be attributed to the grain refinement and the dispersion strengthening by the introduction of TiC and TiB2 particles in the Al matrix. The results show that the newly developed composite inoculant ribbons using GNPs can significantly meliorate the overall mechanical performance of typical Al–Si alloys. [ABSTRACT FROM AUTHOR]