Defect, Microstructure, and Mechanical Property of Ti-6Al-4V Alloy Fabricated by High-Power Selective Laser Melting

Cao, Sheng; Chen, Zhuoer; Lim, Chao Voon Samuel; Yang, Kun; Jia, Qingbo; Jarvis, Tom; Tomus, Dacian; Wu, Xinhua

doi:10.1007/s11837-017-2581-6

Cited by 103 publications

(45 citation statements)

References 28 publications

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“…Many researchers introduced a laser energy density (E D ) concept [8][9][10][11] with the intention of describing the complex dynamic process under the AM process to help further investigate the process-structure-property correlations of AM-built Ti6Al4V alloys. The E D describes a measurement of the averaged applied energy per volume of fabricated material, and the most commonly used energy density equation in SLM can be described by the following equation [9,12].…”

Section: Introductionmentioning

confidence: 99%

Influence of Effective Laser Energy on the Structure and Mechanical Properties of Laser Melting Deposited Ti6Al4V Alloy

Zhang

et al. 2020

Materials

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The laser energy density (ED) is often utilized in many additive manufacturing (AM) processes studies to help researchers to further investigate the process-structure-property correlations of Ti6Al4V alloys. However, the reliability of the ED is still questionable. In this work, a specific empirical calculation equation of the effective laser energy (Ee), which is a dimensionless parameter in laser melting deposition (LMD) processing, was proposed based on the molten pool temperature. The linear regression results and the coefficient of determination prove the feasibility of the Ee equation, which indicates that Ee can more accurately reflect the energy-temperature correlations than the commonly used laser energy density (ED) equation. Additionally, Ti6Al4V components were fabricated by the LMD process with different Ee to investigate the influence of Ee on their structure and mechanical properties. Experimental results show that the detrimental columnar prior β meso-structure can be circumvented and the uniform α + β laths micro-structure can be obtained in LMD Ti6Al4V by a judicious combination of the process parameter (P = 2000 W, V = 12 mm/s, and F = 10.5 g/min) and Ee (7.98 × 105) with excellent tensile strength (1006 ± 25 MPa) and elongation (14.9 ± 0.6%). Overall, the present work provides an empirical calculation equation to obtain a clearer understanding of the influence of different process parameters and indicates the possibility to fabricate the Ti6Al4V alloy with excellent mechanical properties by parameter optimization in the LMD process.

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Section: Introductionmentioning

confidence: 99%

Influence of Effective Laser Energy on the Structure and Mechanical Properties of Laser Melting Deposited Ti6Al4V Alloy

Zhang

et al. 2020

Materials

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“…In order to achieve desired mechanical properties of metallic products by additive manufacturing (AM), it is important to control the process parameters that affect heat input to the material and the cooling rate, which in turn affect the microstructure. In AM, there are a large number of tunable process parameters [1][2][3][4][5] and relatively complex thermal history [6] that results in microstructural changes. As one of many AM processes [6,7], the selective laser melting (SLM) process uses a focused laser beam to melt consecutive layers of metal powder.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The SLM process has a faster cooling rate than the electron beam melting (EBM) process due to the argon atmosphere in SLM having higher thermal conductivity than a vacuum in EBM [9] and that the build platform is kept at a lower tem-perature~100°C [3]. The fast cooling rate results in the formation of predominant martensitic α′ microstructure [3,10,11], where prior β grains grow epitaxially throughout the deposition layers [3,8,[12][13][14]. It renders a material with high strength and low ductility, residual stresses [15], solidification texture [16], and twins [17], which is opposite to the EBM-built material that has a coarser basketweave [4] microstructure and little residual stresses [18].…”

Section: Introductionmentioning

confidence: 99%

“…Fine microstructure zones (FMZ) are formed around a coarse microstructure zone (CMZ), which can potentially affect the mechanical properties. The size of the BMP has been shown to correlate with the hatch spacing [3,10,12], where an increase in hatch spacing renders an increased size of the BMP. Thijs et al [28] investigated different scanning strategies for SLM built Ti-6Al-4V and found the morphology of the BMP varies.…”

Section: Introductionmentioning

confidence: 99%

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Microstructural characterization of binary microstructure pattern in selective laser-melted Ti-6Al-4V

Neikter

Huang

2019

Int J Adv Manuf Technol

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Selective laser melting (SLM) is an additive manufacturing process that offers efficient manufacturing of complex parts with good mechanical properties. For SLM, process parameters and post-processing are of importance as they affect the microstructure and consequently the mechanical properties. A feature in the microstructure, which is formed in SLM due to the fast cooling rate, is a binary microstructure pattern (BMP). The BMP is found in the horizontal plane and is formed with various laser scan angles between adjacent layers. The easiest distinguishable strategy is 90°, which renders a shape similar to a chessboard. In this work, the BMP phenomenon was investigated in detail and a microstructural characterization was performed on the fine microstructure zone (FMZ) that separates the coarse microstructure zones (CMZ), by using light optical and scanning electron microscopes (SEM) that were equipped with electron backscattered (EBSD) and energy dispersive x-ray spectroscopy (EDS) detectors. Moreover, the effect of the process parameter hatch distance on the BMP was investigated and the overlapping between neighboring scan tracks in SLM was found to influence the size of the BMP, while the thickness of the FMZ remained constant. Different post-SLM heat treatments were performed and it was shown that the BMP retained unless the heat treatment temperature reached above the β transus temperature. EBSD and β grain reconstruction were performed as well to reveal the columnar β grain orientations. The result showed that each CMZ and FMZ originates from a respective parent β grains.

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Microstructure and Mechanical Property of Ti–5Al–5Mo–5V–3Cr–1Zr Alloy Fabricated by Selective Laser Melting with a Preheated Substrate

et al. 2021

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The high solidification rate of selective laser melting (SLM) induces a nonequilibrium microstructure in as‐fabricated Ti alloys. Herein, a metastable β Ti–5Al–5Mo–5V–3Cr–1Zr alloy is successfully fabricated by SLM on a preheated substrate at 700 °C. The effects of preheating temperature on microstructure and mechanical properties of as‐fabricated specimens is systematically studied. The phase identification and electron microscopic results demonstrate that the 700 °C preheating temperature enables the transformation of metastable β structure into an α + β structure with massive amounts of nanosized α precipitates. Consequently, the SLM‐fabricated specimen after preheating process possesses higher ultimate tensile strength and hardness at 1440 MPa and 8.24 GPa, respectively. This work shows an alternative for SLM to tackle nonequilibrium microstructure and to increase the strength of metastable Ti alloys by introducing high temperature preheating.

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Defect, Microstructure, and Mechanical Property of Ti-6Al-4V Alloy Fabricated by High-Power Selective Laser Melting

Cited by 103 publications

References 28 publications

Influence of Effective Laser Energy on the Structure and Mechanical Properties of Laser Melting Deposited Ti6Al4V Alloy

Influence of Effective Laser Energy on the Structure and Mechanical Properties of Laser Melting Deposited Ti6Al4V Alloy

Microstructural characterization of binary microstructure pattern in selective laser-melted Ti-6Al-4V

Microstructure and Mechanical Property of Ti–5Al–5Mo–5V–3Cr–1Zr Alloy Fabricated by Selective Laser Melting with a Preheated Substrate

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