“…2 a) were more likely to form when a low energy density was applied in sample a (Table 2 ). This could be due to the insufficient melting of Stellite ® 21 matrix or oxygen gas porosity due to the gas atomised powder, observed in previous work for additively manufactured materials as well [ 17 - 19 ]. Fig.…”
“…2 a) were more likely to form when a low energy density was applied in sample a (Table 2 ). This could be due to the insufficient melting of Stellite ® 21 matrix or oxygen gas porosity due to the gas atomised powder, observed in previous work for additively manufactured materials as well [ 17 - 19 ]. Fig.…”
“…The raw material mainly consists of Al and Si with little Fe, Cu, Re, and other elements. The true density of this powder (see Table 2) is 2.6486 g/cm 3 . The particle size distribution is d 10 = 16.39 µm, d 50 = 25.39 µm, d 90 = 49.78 µm.…”
Section: Powder Characterizationmentioning
confidence: 99%
“…Al-Si alloys are lightweight materials with good castability and excellent mechanical properties [1][2][3]. The Al-Si alloys can be catalogued into three types based on silicon content, which are: (1) hypoeutectic (<10 wt.% Si), ( 2) eutectic (10-13 wt.% Si), and (3) hypereutectic (>13 wt.% Si).…”
Section: Introductionmentioning
confidence: 99%
“…Due to the high reflectivity, low laser absorptivity, high thermal conductivity [3], and high susceptibility to oxidation [13] of the Al-Si alloy powder, various kinds of defects (i.e., porosity, cracks, and surface defects [3,13,31,32]) arise in the SLMed Al-Si alloy parts, which are adverse to their mechanical properties and seriously affect the application of these materials [3,13]. A lot of measures have been taken to produce as-built parts with less or even no defects and high mechanical properties.…”
The objective of the study is to investigate the corresponding microstructure and mechanical properties, especially bending strength, of the hypereutectic Al-Si alloy processed by selective laser melting (SLM). Almost dense Al-22Si-0.2Fe-0.1Cu-Re alloy is fabricated from a novel type of powder materials with optimized processing parameters. Phase analysis of such Al-22Si-0.2Fe-0.1Cu-Re alloy shows that the solubility of Si in Al matrix increases significantly. The fine microstructure can be observed, divided into three zones: fine zones, coarse zones, and heat-affected zones (HAZs). Fine zones are directly generated from the liquid phase with the characteristic of petaloid structures and bulk Al-Si eutectic. Due to the fine microstructure induced by the rapid cooling rate of SLM, the primary silicon presents a minimum average size of ~0.5 μm in fine zones, significantly smaller than that in the conventional produced hypereutectic samples. Moreover, the maximum value of Vickers hardness reaches ~170 HV0.2, and bending strength increases to 687.70 MPa for the as-built Al-22Si-0.2Fe-0.1Cu-Re alloys parts, which is much higher than that of cast counterparts. The formation mechanism of this fine microstructure and the enhancement reasons of bending strength are also discussed.
“…Fatigue fracture in SLM parts originates from their internal defects. (Rao et al, 2019) (Günther et al, 2017) (Beevers et al, 2018) Therefore, as the mechanical properties of SLM parts are significantly affected by the internal defects present in them, computed tomography (CT) has been used to detect the presence of the defects in SLM parts (Snell et al, 2020) (Sangid et al, 2020) (Wits et al, 2016) (Kasperovich et al, 2016). However, from the viewpoint of strength design, it is necessary to determine the internal defect size and investigate its effect on the fatigue characteristics of SLM parts before production.…”
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