Selective laser melting of Ti6Al4V alloy: Process parameters, defects and post-treatments

Singla, Anil Kumar; Banerjee, Mainak; Sharma, Aman; Singh, Jagtar; Bansal, Ankur; Gupta, Munish Kumar; Khanna, Navneet; Shahi, A. S.; Goyal, Deepak Kumar

doi:10.1016/j.jmapro.2021.01.009

Cited by 194 publications

(59 citation statements)

References 136 publications

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“…Recently, Cao et al [ 37 ] reviewed the process, microstructure and post-processes of Ti6Al4V alloy produced by L-PBF. Additionally, process parameters, post-treatments and defects of Ti6Al4V alloy produced by L-PBF were reviewed by Singla et al [ 38 ].…”

Section: Solidification Microstructure Evolution Within Pbf-lbmentioning

confidence: 99%

“…For the martensitic microstructure, as commonly found via maximum heating and cooling rates can reach of 10 6 K/s and 10 5 K/s, respectively [ 42 ]. Additionally, some metallurgical features of Ti6Al4V alloy such as α colony size, α lamellae size, α lamellae thickness and β grain size affect the mechanical properties [ 38 ]. During the L-PBF process, the acicular martensite α’ within the columnar prior-β grains is formed in the microstructure of Ti6Al4V alloy produced by L-PBF shown in Fig.…”

Section: Solidification Microstructure Evolution Within Pbf-lbmentioning

confidence: 99%

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Digitisation of metal AM for part microstructure and property control

et al. 2022

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Metal additive manufacturing, which uses a layer-by-layer approach to fabricate parts, has many potential advantages over conventional techniques, including the ability to produced complex geometries, fast new design part production, personalised production, have lower cost and produce less material waste. While these advantages make AM an attractive option for industry, determining process parameters which result in specific properties, such as the level of porosity and tensile strength, can be a long and costly endeavour. In this review, the state-of-the-art in the control of part properties in AM is examined, including the effect of microstructure on part properties. The simulation of microstructure formation via numerical simulation and machine learning is examined which can provide process quality control and has the potential to aid in rapid process optimisation via closed loop control. In-situ monitoring of the AM process, is also discussed as a route to enable first time right production in the AM process, along with the hybrid approach of AM fabrication with post-processing steps such as shock peening, heat treatment and rolling. At the end of the paper, an outlook is presented with a view towards potential avenues for further research required in the field of metal AM.

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Section: Solidification Microstructure Evolution Within Pbf-lbmentioning

confidence: 99%

Section: Solidification Microstructure Evolution Within Pbf-lbmentioning

confidence: 99%

Digitisation of metal AM for part microstructure and property control

et al. 2022

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“…The development of these residual stresses is the result of the high thermal gradients that built up in the object and depends on the laser scan as well as on the geometry of the part (Agius et al , 2018; Yakout et al , 2020; Chen et al , 2021). A comprehensive study on the α variants and prior β grains during post-process heat treatments is reported by Yang et al (2017) and Singla et al (2021).…”

Section: Introductionmentioning

confidence: 99%

Study of anisotropy through microscopy, internal friction and electrical resistivity measurements of Ti-6Al-4V samples fabricated by selective laser melting

Nespoli

Bennato

Villa

et al. 2022

RPJ

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Purpose This paper aims to investigate the microstructural anisotropy of Ti-6Al-4V samples fabricated by selective laser melting. Design/methodology/approach Specimens are fabricated through a Renishaw AM400 selective laser melting machine. Three microstructures (as-built, 850°C annealed and 1,050°C annealed) and two building orientations, parallel (PA) and perpendicular (PE) to the building platform, are considered. Starting from in-depth microscopic observations and comprehensive electron backscattered diffraction imaging, the study addresses non-conventional techniques such as internal friction and electrical resistivity measurements to assess the anisotropy of the fabricated parts. Findings Microscope observations highlight a fine texture with columnar grains parallel to the building direction in the as-built and 850°C annealed samples. Besides, coarse grains characterized the 1,050°C annealed specimens. Internal friction measurements pointed out the presence of internal stress while storage modulus analyses appear sensitive to texture. Electrical resistivity is resulted to be dependent on grain orientation. Originality/value The work uses some novel characterization techniques to study the anisotropy and internal stresses of Ti-6Al-4V samples processed by selective laser melting. Mechanical spectroscopy results suitable in this kind of study, as it mimics the operating conditions of the material.

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“…Surface integrity issues could be because of fact that they used dry machining. Singla et al [36] considered various post processing techniques (shot peening, heat treatments, hot isostatic pressing and sand blasting) by different researchers on Ti6Al4V L-PBF part in order to enhance the mechanical and metallurgical properties. They found that combination of post processing methods is worth exploring for reducing the defects and improving the performance of Ti6Al4V L-PBF part in different engineering applications.…”

Section: Introductionmentioning

confidence: 99%

Investigations on the Effect of Layers’ Thickness and Orientations in the Machining of Additively Manufactured Stainless Steel 316L

et al. 2021

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Laser-powder bed fusion (L-PBF) process is a family of modern technologies, in which functional, complex (3D) parts are formed by selectively melting the metallic powders layer-by-layer based on fusion. The machining of L-PBF parts for improving their quality is a difficult task. This is because different component orientations (L-PBF-layer orientations) produce different quality of machined surface even though the same cutting parameters are applied. In this paper, stainless steel grade SS 316L parts from L-PBF were subjected to the finishing (milling) process to study the effect of part orientations. Furthermore, an attempt is made to suppress the part orientation effect by changing the layer thickness (LT) of the parts during the L-PBF process. L-PBF parts were fabricated with four different layer thicknesses of 30, 60, 80 and 100 μm to see the effect of the LT on the finish milling process. The results showed that the layer thickness of 60 μm has significantly suppressed the part orientation effect as compared to the other three-layer thicknesses of 30, 80 and 100 μm. The milling results showed that the three-layer thickness including 30, 80 and 100 μm presented up to a 34% difference in surface roughness among different part orientations while using the same milling parameters. In contrast, the layer thickness of 60 μm showed uniform surface roughness for the three-part orientations having a variation of 5–17%. Similarly, the three-layer thicknesses 30, 80 and 100 μm showed up to a 25%, 34% and 56% difference of axial force (Fa), feed force (Ff) and radial force (Fr), respectively. On the other hand, the part produced with layer thickness 60 μm showed up to 11%, 25% and 28% difference in cutting force components Fa, Ff and Fr, respectively. The three-layer thicknesses 30, 80 and 100 μm in micro-hardness were found to vary by up to 14.7% for the three-part orientation. Negligible micro-hardness differences of 1.7% were revealed by the parts with LT 60 μm across different part orientations as compared to 6.5–14% variations for the parts with layer thickness of 30, 80 and 100 μm. Moreover, the parts with LT 60 μm showed uniform and superior surface morphology and reduced edge chipping across all the part orientations. This study revealed that the effect of part orientation during milling becomes minimum and improved machined surface integrity is achieved if the L-PBF parts are fabricated with a layer thickness of 60 μm.

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Selective laser melting of Ti6Al4V alloy: Process parameters, defects and post-treatments

Cited by 194 publications

References 136 publications

Digitisation of metal AM for part microstructure and property control

Digitisation of metal AM for part microstructure and property control

Study of anisotropy through microscopy, internal friction and electrical resistivity measurements of Ti-6Al-4V samples fabricated by selective laser melting

Investigations on the Effect of Layers’ Thickness and Orientations in the Machining of Additively Manufactured Stainless Steel 316L

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