Effect of solid solution plus double aging on microstructural characterization of 7075 Al alloys fabricated by selective laser melting (SLM)

Sun, Sihao; Liu, Peng; Hu, Jiaying; Hong, Chen; Qiao, Xue; Liu, Siyu; Zhang, Ruiyun; Wu, Chengge

doi:10.1016/j.optlastec.2019.02.006

Cited by 50 publications

(19 citation statements)

References 24 publications

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“…According to the XRD results, the peak near 45 degree increased significantly after heat treatment. Combined with the observation of the microstructure, it was inferred that Al7Cu23Ni was the main strengthening phase and preferentially precipitated at the grain boundary [22,41]. Therefore, Al7Cu23Ni failed to delay the propagation of fatigue cracks during the fatigue test.…”

Section: Fatigue Characteristicsmentioning

confidence: 97%

“…The SLM process exhibits the advantages of cost-effective mold development, the manufacturing of complex geometric shapes, customization, and high dimensional accuracy [12][13][14][15]. The SLM process is typically applied to aluminum alloys, such as Al-Si-Mg [12,[16][17][18], Al-Mg-Sc-Zr [19][20][21], and 7075 aluminum alloys [22,23]. Al-Ni alloys exhibit excellent fluidity [3] and are suitable for the SLM process.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure, Mechanical Properties, and Fatigue Fracture Characteristics of High-Fracture-Resistance Selective Laser Melting Al-Ni-Cu Alloys

Chang

Zhao

Hung

2021

Metals

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Al-Ni-Cu alloys are used in energy, automotive, and aerospace industries because of their excellent mechanical properties, corrosion resistance, and high-temperature stability. In this study, Al-Ni-Cu alloy powder was subjected to selective laser melting (SLM). The SLM Al-Ni-Cu alloy was manufactured using appropriate printing parameters, and its properties were investigated. The results revealed that the As-printed material exhibited a typical melting pool stack structure, with an ultimate tensile strength of 725 MPa but a high brittleness effect (low ductility). After traditional heat treatment, the melting pool structure did not completely disappear. The strengthening phase Al7Cu23Ni precipitated from the boundary of the melting pools; thus, the Al-Ni-Cu alloy maintained high strength (>500 MPa) and considerably increased ductility (>10%). The SLM Al-Ni-Cu alloy has considerable industrial application potential; therefore, increasing the heat treatment temperature or extending the heat treatment time in the future works can promote the decomposition of the melting pool boundary and solve the problem related to the aggregation behavior of the precipitation phase, thereby improving the fatigue life of the alloy.

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Section: Fatigue Characteristicsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Microstructure, Mechanical Properties, and Fatigue Fracture Characteristics of High-Fracture-Resistance Selective Laser Melting Al-Ni-Cu Alloys

Chang

Zhao

Hung

2021

Metals

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“…On the other hand, in the as-fabricated SLM alloys, the distinct lamellar morphology of the h phase is absent ( Figure 49 c1,c2). Fine particles (η phase) are found in the interdendritic areas, maintaining a high degree of supersaturation, which can subsequently result in the precipitation of the η′ phase during T6 heat treatment [ 183 , 188 , 189 , 190 ]. The microstructure further changes in the T6 heat-treated SLM samples, where the η particles are hardly visible within the Al matrix and are mostly situated at the Al grain boundaries ( Figure 49 d1,d2).…”

Section: Microstructurementioning

confidence: 99%

“…The nano-hardness was not uniform in different regions of the melt pool under keyhole mode conditions with the highest measured nano-hardness at the bottom [ 184 ]. Compressive tests for SLM Al7075 and SLM Al7050 alloy were conducted by Sistiaga et al [ 95 ] and Singh et al [ 188 ], respectively. The yield strength increases from 279 ± 10 MPa for the as-prepared state to 338 ± 13 MPa for the heat-treated Al7050 + 4 wt.%Si alloy.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Selective Laser Melting of Aluminum and Its Alloys

et al. 2020

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The laser-based powder bed fusion (LBPF) process or commonly known as selective laser melting (SLM) has made significant progress since its inception. Initially, conventional materials like 316L, Ti6Al4V, and IN-718 were fabricated using the SLM process. However, it was inevitable to explore the possible fabrication of the second most popular structural material after Fe-based alloys/steel, the Al-based alloys by SLM. Al-based alloys exhibit some inherent difficulties due to the following factors: the presence of surface oxide layer, solidification cracking during melt cooling, high reflectivity from the surface, the high thermal conductivity of the metal, poor flowability of the powder, low melting temperature, etc. Researchers have overcome these difficulties to successfully fabricate the different Al-based alloys by SLM. However, there exists no review dealing with the fabrication of different Al-based alloys by SLM, their fabrication issues, microstructure, and their correlation with properties in detail. Hence, the present review attempts to introduce the SLM process followed by a detailed discussion about the processing parameters that form the core of the alloy development process. This is followed by the current research status on the processing of Al-based alloys and microstructure evaluation (including defects, internal stresses, etc.), which are dealt with on the basis of individual Al-based series. The mechanical properties of these alloys are discussed in detail followed by the other important properties like tribological properties, fatigue properties, etc. Lastly, an outlook is given at the end of this review.

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“…Limited literature is available on the processing of high-strength Al alloys through L-PBF, and specifically, on heat-treatable wrought alloys (2xx.x, 6xx.x and 7xx.x) (Ahuja et al , 2014; Casati et al , 2017; Dadbakhsh et al , 2018; Carluccio et al , 2018; Montero-Sistiaga et al , 2016; Sun et al , 2019). Conventionally produced wrought Al alloys possess ultimate tensile stress (UTS) in the range of 200–575 MPa and ductility of 3–20%, depending on the deployed thermomechanical processing route during manufacturing (Davis, 1993).…”

Section: Introductionmentioning

confidence: 99%

Additive manufacturing of aluminium alloy 2024 by laser powder bed fusion: microstructural evolution, defects and mechanical properties

Kumar

Gibbons

Das

et al. 2021

RPJ

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Purpose The purpose of this study is to investigate the microstructural evolution of high-strength 2024 Al alloy prepared by the laser powder bed fusion (L-PBF) additive manufacturing (AM) route. The high-strength wrought Al alloy has typically been unsuitable for AM due to its particular solidification characteristics such as hot cracking, porosity and columnar grain growth. Design/methodology/approach In this research work, samples were fabricated using L-PBF under various laser energy densities by varying laser power and scan speed. The microstructural features that developed during the solidification are correlated with operating laser parameters. In addition, finite element modelling (FEM) was performed to understand the experimentally observed results. Findings Microstructure evolution and defect formation have been assessed, quantified and correlated with operating laser parameters. Thermal behaviour of samples was predicted using FEM to support experimental observations. An optimised combination of intermediate laser power and scan speed produced the least defects. Higher energy density increased hot tearing along the columnar grain boundaries, while lower energy density promoted void formation. From the quantitative results, it is evident that with increasing energy density, both the top surface and side wall roughness initially reduced till a minimum and then increased. Hardness and compressive strength were found to decrease with increasing power density due to stress relaxation from hot tearing. Originality/value This research work examined how L-PBF processing conditions influence the microstructure, defects, surface roughness and mechanical properties. The results indicates that complete elimination of solidification cracks can be only achieved by combining process optimisation and possible grain refining strategies.

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Effect of solid solution plus double aging on microstructural characterization of 7075 Al alloys fabricated by selective laser melting (SLM)

Cited by 50 publications

References 24 publications

Microstructure, Mechanical Properties, and Fatigue Fracture Characteristics of High-Fracture-Resistance Selective Laser Melting Al-Ni-Cu Alloys

Microstructure, Mechanical Properties, and Fatigue Fracture Characteristics of High-Fracture-Resistance Selective Laser Melting Al-Ni-Cu Alloys

Selective Laser Melting of Aluminum and Its Alloys

Additive manufacturing of aluminium alloy 2024 by laser powder bed fusion: microstructural evolution, defects and mechanical properties

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