Influence of position and laser power on thermal history and microstructure of direct laser fabricated Ti–6Al–4V samples

Qian, Lu; Mei, Junfa; Liang, Jintao; Wu, Xinhua

doi:10.1179/174328405x21003

Cited by 134 publications

(67 citation statements)

References 17 publications

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“…[15][16][17] It is very difficult to predict the microstructure of the DMD sample because of its very complex thermal history. Recently, Qian et al [14] have developed a finite element model for temperature history prediction in direct laser deposition samples. According to their model, during laser deposition, the very top layer cools from the liquid at a rate of~7 9 10 4 K s -1 directly to a temperature significantly below the martensite start temperature.…”

Section: Discussionmentioning

confidence: 99%

Fabrication of Ti-6Al-4V Scaffolds by Direct Metal Deposition

Dinda

Song

Mazumder

2008

Metall Mater Trans A

216

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Direct metal deposition (DMD) is a rapid laser-aided deposition method that can be used to manufacture near-net-shape components from their computer aided design (CAD) files. The method can be used to produce fully dense or porous metallic parts. The Ti-6Al-4V alloy is widely used as an implantable material mainly in the application of orthopedic prostheses because of its high strength, low elastic modulus, excellent corrosion resistance, and good biocompatibility. In the present study, Ti-6Al-4V scaffold has been fabricated by DMD technology for patient specific bone tissue engineering. Good geometry control and surface finish have been achieved. The structure and properties of the scaffolds were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and tension test. The microstructures of laser-deposited Ti-6Al-4V scaffolds are fine Widmansta¨tten in nature. The tensile and yield strengths of the as-deposited Ti-6Al-4V were 1163 ± 22 and 1105 ± 19 MPa, respectively, which are quite higher than the ASTM limits (896 and 827 MPa) for Ti-6Al-4V implants. However, the ductility of the as-deposited sample was very low (~4 pct), which is well below the ASTM limit (10 pct). After an additional heat treatment (sample annealed at 950°C followed by furnace cooling), both strength (UTS1 045 ± 16, and YS~959 ± 12 MPa) and ductility (~10.5 ± 1 pct) become higher than ASTM limits for medical implants.

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Section: Discussionmentioning

confidence: 99%

Fabrication of Ti-6Al-4V Scaffolds by Direct Metal Deposition

Dinda

Song

Mazumder

2008

Metall Mater Trans A

216

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“…Especially for complex shapes and small quantities, the fabrication of net shape components by additive layer manufacturing can reduce the costs by omitting extensive machining and production of scrap. Several techniques are considered, including direct laser fabrication [1][2][3][4][5][6][7][8][9][10], electron beam freeform fabrication [11][12][13] and tungsten inert gas welding [14][15][16]. The technique used in this paper is shaped metal deposition (SMD), which is a net shape tungsten inert gas welding process patented by Rolls-Royce.…”

Section: Introductionmentioning

confidence: 99%

Mechanical properties of Ti-6Al-4V specimens produced by shaped metal deposition

Baufeld

Biest

2009

Science and Technology of Advanced Materials

141

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Shaped metal deposition is a novel technique to build near net-shape components layer by layer by tungsten inert gas welding. Especially for complex shapes and small quantities, this technique can significantly lower the production cost of components by reducing the buy-to-fly ratio and lead time for production, diminishing final machining and preventing scrap. Tensile testing of Ti-6Al-4V components fabricated by shaped metal deposition shows that the mechanical properties are competitive to material fabricated by conventional techniques. The ultimate tensile strength is between 936 and 1014 MPa, depending on the orientation and location. Tensile testing vertical to the deposition layers reveals ductility between 14 and 21%, whereas testing parallel to the layers gives a ductility between 6 and 11%. Ultimate tensile strength and ductility are inversely related. Heat treatment within the α + β phase field does not change the mechanical properties, but heat treatment within the β phase field increases the ultimate tensile strength and decreases the ductility. The differences in ultimate tensile strength and ductility can be related to the α lath size and orientation of the elongated, prior β grains. The micro-hardness and Young's modulus are similar to conventional Ti-6Al-4V with low oxygen content.

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“…These results are in agreement with results published by other authors. In particular the diffusional transformation of β phase in Ti-6Al-4V components produced by laser assisted deposition at low scanning speeds was verified by .5 mm/s) (Kelly & Kampe, 2004a) and .0 mm/s) (Qian et al, 2005), whereas the occurrence of a martensitic transformation at higher speeds was confirmed by Groh (d. Groh, 2006). (Crespo & Vilar, 2010).…”

Section: Influence Of Substrate Temperaturementioning

confidence: 68%

Modelling of Heat Transfer and Phase Transformations in the Rapid Manufacturing of Titanium Components

Crespo¹

2011

Convection and Conduction Heat Transfer

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Influence of position and laser power on thermal history and microstructure of direct laser fabricated Ti–6Al–4V samples

Cited by 134 publications

References 17 publications

Fabrication of Ti-6Al-4V Scaffolds by Direct Metal Deposition

Fabrication of Ti-6Al-4V Scaffolds by Direct Metal Deposition

Mechanical properties of Ti-6Al-4V specimens produced by shaped metal deposition

Modelling of Heat Transfer and Phase Transformations in the Rapid Manufacturing of Titanium Components

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