Microstructure and deformation behavior of Ti-6Al-4V alloy by high-power laser solid forming

Ren, Yongming; Lin, Xin; Fu, Xin; Tan, Hua; Chen, J.; Huang, Wei

doi:10.1016/j.actamat.2017.04.026

Cited by 248 publications

(47 citation statements)

References 36 publications

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“…In the literature, it well documented that slip or shear bands play an important role during plastic deformation processes [43][44][45][46][47][48][49]. For instance, at the micro scale, the slip bands [44,47,49] and shear bands [44,46,[47][48][49] can be treated as a symbol of plastic strain localization in Ti alloys, which may relate to nucleation and propagation of local voids. Furthermore, it has been proved that shear bands can be treated as vulnerable sites for nucleation, growth and coalescence of voids in the way of numerical simulation [25] and experiments [49][50][51].…”

Section: Microscopic Damage Measurementmentioning

confidence: 99%

Analysis of shear stress promoting void evolution behavior in an α/β Ti alloy with fully lamellar microstructure

Liu¹,

Maire

Adrien

et al. 2018

Materials Science and Engineering: A

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With the help of X-ray synchrotron tomography, in situ tensile tests have been performed on Ti-6Al-4V titanium alloy with full lamellar microstructure. The rendered 3D images have shown that void could nucleate as soon as the material yields, although local stress triaxiality (T=0.472) seems not to be high and even tends to maintain a constant value in the following damage steps(T=0.474~0.510). It can be inferred that local stress triaxiality could not be the dominating factor during damage development in this current work.

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Section: Microscopic Damage Measurementmentioning

confidence: 99%

Analysis of shear stress promoting void evolution behavior in an α/β Ti alloy with fully lamellar microstructure

Liu¹,

Maire

Adrien

et al. 2018

Materials Science and Engineering: A

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“…6 Roughness values of milled specimens determined by profilometry due to the thermal boundary conditions of the additive manufacturing process. This morphology consisting of narrow α laths is typical of Ti-6Al-4V manufactured by LMD as a result of the high cooling rates and is strongly influenced by the process parameters, such as laser power or scanning speed [42,43]. Due to the high temperatures and mechanical stresses which occur during machining, severe plastic deformation and phase transformation can often be found in the subsurface area of a material after mechanical processing.…”

Section: Microstructural Analysismentioning

confidence: 99%

Hybrid manufacturing of titanium Ti-6Al-4V combining laser metal deposition and cryogenic milling

Moritz

Seidel

Kopper

et al. 2020

Int J Adv Manuf Technol

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Hybrid manufacturing, which, e.g., combines additive manufacturing with conventional machining processes, can be a way of overcoming limitations currently encountered in additive manufacturing. Cryogenic milling might be a viable option for hard-tocut materials, as it leaves a contamination-free surface and can increase surface quality and tool life compared to conventional cooling concepts. In this study, the influence of cryogenic milling with carbon dioxide on titanium Ti-6Al-4V specimens manufactured with laser metal deposition (LMD) was investigated regarding tool wear and surface integrity in comparison to dry machining and machining with cooling lubricants. Moreover, additional layers of material were deposited on top of conventionally and cryogenically machined surfaces by means of LMD. The interface zone was then examined for defects. The milling process was closely monitored by means of thermal and high-speed imaging. Optical and tactile surface analysis provided evidence that lower roughness values and improved surface qualities could be obtained with cryogenic machining in comparison to dry machining. Moreover, significantly less tool wear was observed when a cryogenic cooling medium was applied. Although the utilization of conventional cooling lubricants resulted in satisfying surface qualities, substantial residual contamination on the milled surface was detected by means of fluorescence analysis. These contaminants are suspected to cause defects when the next layer of material is deposited. This is supported by the fact that pores were found in the weld bead applied on top of the milled specimens by means of LMD. Conversely, cryogenic machining resulted in very clean surfaces due to the residue-free evaporation of the coolant. Hence, a good metallurgical bonding between the weld bead and the milled substrate could be achieved. The results indicate the great potential of cryogenic milling in hybrid manufacturing, especially in terms of intermediate machining, as it provides residue-free surfaces for subsequent material deposition without an additional cleaning step and can significantly prolongate tool life.

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“…The local equilibrium assumption of the classical solidification theory had been considered not to be applicable for the analysis of this process. On the other hand, some works have reported experimental observations of the CET in solidification of DED [6]. They suggest MPFM based on the local (quasi-)equilibrium assumption could possibly be adopted for the solidification simulation of DED process as well.…”

Section: Introductionmentioning

confidence: 99%

“…Many researchers consider the solidification map useful tool to predict solidification microstructure for AM process and have attempted to produce it by experiment [1,[6][7][8]. We attempt to investigate applicability of MPFM coupled with CALPHAD database for solidification simulation to DED process of a titanium alloy with 1773 Solid Freeform Fabrication 2018: Proceedings of the 29th Annual International Solid Freeform Fabrication Symposium -An Additive Manufacturing Conference Reviewed Paper composition of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si (wt.%).…”

Section: Introductionmentioning

confidence: 99%

Solidification simulation of direct energy deposition process by multi-phase field method coupled with thermal analysis

Shimono¹,

Oba²,

Nomoto

2019

Modelling Simul. Mater. Sci. Eng.

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The multi-phase field method coupled with the thermodynamics database of calculation of phase diagrams has been successfully applied to simulation of solidification microstructure evolutions in engineering casting processes. As multi-phase field method is based on the local (quasi-)equilibrium assumption in solidification theory [1], applying this method to solidification of additive manufacturing processes is not studied enough because of extremely large cooling rate and temperature gradient conditions. On the other hand, some researchers have reported experimental observations of the columnar-to-equiaxed transition in the solidification of the additive manufacturing processes including the direct energy deposition. They suggest that the local (quasi-)equilibrium assumption can be applied to solidification of additive manufacturing processes [2]. In this study, solidification microstructures of titanium alloys in direct energy deposition are calculated by multi-phase field method. Temperature distributions obtained by thermal analyses using finite element method are adapted to multi-phase field method. The microstructure evolution of columnar-to-equiaxed transition is confirmed. The results are summarized in a solidification map for direct energy deposition process conditions.

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Microstructure and deformation behavior of Ti-6Al-4V alloy by high-power laser solid forming

Cited by 248 publications

References 36 publications

Analysis of shear stress promoting void evolution behavior in an α/β Ti alloy with fully lamellar microstructure

Analysis of shear stress promoting void evolution behavior in an α/β Ti alloy with fully lamellar microstructure

Hybrid manufacturing of titanium Ti-6Al-4V combining laser metal deposition and cryogenic milling

Solidification simulation of direct energy deposition process by multi-phase field method coupled with thermal analysis

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