Selective laser melting additive manufacturing of in situ Al2Si4O10/Al composites: Microstructural characteristics and mechanical properties

2016 ◽  
Vol 51 (4) ◽  
pp. 519-532 ◽  
Author(s):  
Jiubin Jue ◽  
Dongdong Gu
Keyword(s):  
Mechanical Properties ◽  
Selective Laser Melting ◽  
Processing Parameters ◽  
Dry Sliding Wear ◽  
Microstructural Development ◽  
Laser Melting ◽  
Composite Powders ◽  
Wear Performance ◽  
Al Matrix

The advanced selective laser melting technology was employed to prepare in situ Al based composites. Relationship among selective laser melting processing parameters, microstructures and resultant mechanical properties had been established. It turned out that in situ Al2Si4O10/Al composites were successfully fabricated by selective laser melting of Al2O3/AlSi10Mg composite powders. Due to the overlap between neighboring tracks and the remelting of previously solidified layers, two distinguished zones consisting of track core and track overlap were produced in laser induced melt pool. The two zones, respectively experienced different thermal histories, thus leading to the variation of cooling rate, which had a significant influence on the microstructural development and resultant mechanical performances. The track core mainly consisted of remarkably refined cellular dendritic Al matrix decorated with uniformly distributed ring-structured Al2Si4O10 reinforcements, while the track overlap was characterized with comparatively coarse columnar dendritic Al matrix as well as the coarse Al2Si4O10 reinforcements. At the optimal v of 500 mm/s, the obtained dynamic nanohardness ( H d) of track core ( H d = 3.79 GPa) and track overlap ( H d = 3.52 GPa) for selective laser melting processed composites part both showed tremendous enhancement upon that of unreinforced Al part ( H d = 0.58 GPa). The dry sliding wear tests indicated that the optimally prepared Al2Si4O10/Al composites part exhibited excellent wear performance with a considerably low coefficient of friction of 0.32 and a significantly reduced wear rate of 4.52 × 10−5 mm3 N−1 m−1. The formed consecutive protective adherent tribolayer on the worn surface and the significantly enhanced hardness of the composites well accounted for the superior wear performance.

scholarly journals High Bending Strength Hypereutectic Al-22Si-0.2Fe-0.1Cu-Re Alloy Fabricated by Selective Laser Melting

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 528
Author(s):  
Chunyue Yin ◽  
Zhehao Lu ◽  
Xianshun Wei ◽  
Biao Yan ◽  
Pengfei Yan
Keyword(s):  
Selective Laser Melting ◽  
Bending Strength ◽  
Primary Silicon ◽  
Processing Parameters ◽  
Powder Materials ◽  
Laser Melting ◽  
Maximum Value ◽  
Fine Microstructure ◽  
Average Size ◽  
Al Matrix

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.

scholarly journals Mechanical Properties of In-Situ Synthesis of Ti-Ti3Al Metal Composite Prepared by Selective Laser Melting

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1121 ◽  
Author(s):  
Li ◽  
Liang ◽  
Tian ◽  
Yang ◽  
Xie ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Selective Laser Melting ◽  
Melting Process ◽  
In Situ Synthesis ◽  
Metal Composite ◽  
Dispersion Strengthening ◽  
Laser Melting ◽  
Compression Properties

Titanium composite strengthened by Ti3Al precipitations is considered to be one of the excellent materials that is widely used in engineering. In this work, we prepared a kind of Ti-Ti3Al metallic composite by in-situ synthesis technology during the SLM (selective laser melting) process, and analyzed its microstructure, wear resistance, microhardness, and compression properties. The results showed that the Ti-Ti3Al composite, prepared by in-situ synthesis technology based on SLM, had more homogeneous Ti3Al-enhanced phase dispersion strengthening structure. The grain size of the workpiece was about 1 μm, and that of the Ti3Al particle was about 200 nm. Granular Ti3Al was precipitated after the aluminum-containing workpiece formed, with a relatively uniform distribution. Regarding the mechanical properties, the hardness (539 HV) and the wear resistance were significantly improved when compared with the Cp-Ti workpiece. The compressive strength of the workpiece increased from 886.32 MPa to 1568 MPa, and the tensile strength of the workpiece increased from 531 MPa to 567 MPa after adding aluminum. In the future, the combination of in-situ synthesis technology and SLM technology can be used to flexibly adjust the properties of Ti-based materials.

scholarly journals Investigation of Porosity and Mechanical Properties of Graphene Nanoplatelets-Reinforced AlSi10 Mg by Selective Laser Melting

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Yachao Wang ◽  
Jing Shi ◽  
Shiqiang Lu ◽  
Weihan Xiao
Keyword(s):  
Mechanical Properties ◽  
Selective Laser Melting ◽  
Quantitative Relationship ◽  
Tensile Tests ◽  
High Energy ◽  
Graphene Nanoplatelets ◽  
Material Strength ◽  
Strengthening Effect ◽  
Laser Melting ◽  
Composite Powders

Graphene possesses many outstanding properties, such as high strength and light weight, making it an ideal reinforcement for metal matrix composite (MMCs). Meanwhile, fabricating MMCs through laser-assisted additive manufacturing (LAAM) has attracted much attention in recent years due to the advantages of low waste, high precision, short production lead time, and high flexibility. In this study, graphene-reinforced aluminum alloy AlSi10 Mg is fabricated using selective laser melting (SLM), a typical LAAM technique. Composite powders are prepared using high-energy ball milling. Room temperature tensile tests are conducted to evaluate the mechanical properties. Scanning electron microscopy observations are conducted to investigate the microstructure and fracture surface of obtain composite. It is found that adding graphene nanoplatelets (GNPs) significantly increases porosity, which offsets the enhancement of tensile performance as a result of GNPs addition. Decoupling effort is then made to separate the potential beneficial effects from GNPs addition and the detrimental effect from porosity increase. For this purpose, the quantitative relationship between porosity and material strength is obtained. Taking into consideration the strength reduction caused by the increased porosity, the strengthening effect of GNPs turns out to be significant, which reaches 60.2 MPa.

scholarly journals Effect of Post Processing Heat Treatment Routes on Microstructure and Mechanical Property Evolution of Haynes 282 Ni-Based Superalloy Fabricated with Selective Laser Melting (SLM)

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 629
Author(s):  
Anagh Deshpande ◽  
Subrata Deb Nath ◽  
Sundar Atre ◽  
Keng Hsu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Property ◽  
High Temperature ◽  
Selective Laser Melting ◽  
Laser Melting ◽  
Step Heat Treatment ◽  
Microstructure And Mechanical Property ◽  
In Situ Heat Treatment

Selective laser melting (SLM) is one of the most widely used additive manufacturing technologies. Fabricating nickel-based superalloys with SLM has garnered significant interest from the industry and the research community alike due to the excellent high temperature properties and thermal stability exhibited by the alloys. Haynes-282 alloy, a γ′-phase strengthened Ni-based superalloy, has shown good high temperature mechanical properties comparable to alloys like R-41, Waspaloy, and 263 alloy but with better fabricability. A study and comparison of the effect of different heat-treatment routes on microstructure and mechanical property evolution of Haynes-282 fabricated with SLM is lacking in the literature. Hence, in this manuscript, a thorough investigation of microstructure and mechanical properties after a three-step heat treatment and hot isostatic pressing (HIP) has been conducted. In-situ heat-treatment experiments were conducted in a transmission electron microscopy (TEM) to study γ′ precipitate evolution. γ′ precipitation was found to start at 950 °C during in-situ heat-treatment. Insights from the in-situ heat-treatment were used to decide the aging heat-treatment for the alloy. The three-step heat-treatment was found to increase yield strength (YS) and ultimate tensile strength (UTS). HIP process enabled γ′ precipitation and recrystallization of grains of the as-printed samples in one single step.

scholarly journals Effects processing parameters and building orientation on the microstructural and mechanical properties of AlSilOMg parts printed by selective laser melting

2021 ◽  
Vol 121 (7) ◽  
Author(s):  
C. Phetolo ◽  
V. Matjeke ◽  
J. van der Merwe
Keyword(s):  
Mechanical Properties ◽  
Selective Laser Melting ◽  
Processing Parameters ◽  
Fractographic Analysis ◽  
Lower Percentage ◽  
Laser Melting ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
Homogeneous Microstructure ◽  
Building Orientation

SYNOPSIS The mechanical properties and microstructure of AlSilOMg alloy samples that were printed by selective laser melting (SLM) were studied to determine the effect of processing parameters and building orientation. After printing, the alloy was stress relieved at 250°C for 2 hours. The microstructures were analysed by optical microscopy and scanning electron microscopy (SEM) to determine the alloy phases and distribution. Phase transformation characteristics of the material were evaluated using differential scanning calorimetry (DSC). Mechanical properties were determined by subjecting the XY- and Z-built samples to tensile and nano-indentation testing. The samples from the tensile tests were then used to perform fractographic analysis by SEM. The microstructural properties in each orientation revealed a non-homogeneous microstructure which was characterized by a semi-elliptical tract and fine silicon precipitates, which were found to be softer along the fusion zone. The DSC thermograms revealed that the material underwent two phase transformations during the first heating cycle. The mechanical properties revealed a higher UTS, higher yield strength, and a lower percentage elongation in the Z orientation than in the XY orientation. Fractographic analysis showed that crack initiation in both orientations started from the surface in a brittle manner due to surface flows, and then propagated via microvoid coalescence. Keywords: AlSi10Mg alloy, additive manufacturing, mechanical propeerties, microstructure.

scholarly journals Uncertainties Induced by Processing Parameter Variation in Selective Laser Melting of Ti6Al4V Revealed by In-Situ X-ray Imaging

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 530
Author(s):  
Zachary A. Young ◽  
Meelap M. Coday ◽  
Qilin Guo ◽  
Minglei Qu ◽  
S. Mohammad H. Hojjatzadeh ◽  
...  
Keyword(s):  
Laser Beam ◽  
Selective Laser Melting ◽  
Small Deviation ◽  
Processing Parameters ◽  
Powder Layer ◽  
Beam Size ◽  
Processing Parameter ◽  
Laser Melting ◽  
Melt Pool

Selective laser melting (SLM) additive manufacturing (AM) exhibits uncertainties, where variations in build quality are present despite utilizing the same optimized processing parameters. In this work, we identify the sources of uncertainty in SLM process by in-situ characterization of SLM dynamics induced by small variations in processing parameters. We show that variations in the laser beam size, laser power, laser scan speed, and powder layer thickness result in significant variations in the depression zone, melt pool, and spatter behavior. On average, a small deviation of only ~5% from the optimized/reference laser processing parameter resulted in a ~10% or greater change in the depression zone and melt pool geometries. For spatter dynamics, small variation (10 μm, 11%) of the laser beam size could lead to over 40% change in the overall volume of the spatter generated. The responses of the SLM dynamics to small variations of processing parameters revealed in this work are useful for understanding the process uncertainties in the SLM process.

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