Material Analysis of Titanium Alloy Produced by Direct Metal Laser Sintering

Direct Metal Laser Sintering (DMLS) is an additive manufacturing technology that can construct medium to small size parts very efficiently in comparison to traditional machining processes. The ability of this technology to grow complex parts made of high strength titanium- and nickel-based alloys led to increasing interest from aerospace, defense, and medical industries. Although the technology allows growing parts close to their final shape, the active surfaces still need a finishing operation such as grinding to meet the tight tolerances and surface finish requirements. Due to the novelty of the DMLS technology, and the relatively recent developments of titanium alloy powders, there is a need for testing and validating the capabilities of the components manufactured through a combination of DMLS and grinding processes. This paper presents the findings of an experimental study focused on the effect of various grinding conditions on the surface integrity of titanium alloy (Ti-6Al-4V) specimens produced using DMLS technology. The goal is to identify dressing and grinding conditions that would result in ground surfaces free of defects such as micro-cracks, discoloration of surfaces and/or burn marks due to high heat generated during grinding. The residual stresses were used to quantify the effect of the grinding conditions on the ground surfaces. These investigations were conducted on an instrumented CNC surface grinding machine, using a silicon-carbide grinding wheel and a water-based fluid. The X-ray diffraction method was used to measure the residual stresses. Two batches of specimens were manufactured for these tests. The growing strategy of the specimens and the presence of apparent defects in material structure are considered some of the main causes for the differences observed in the outcomes of the grinding trials. The results of these investigations support the need for continuing research in the additive manufacturing field to develop methods and technologies that will ensure a high level of consistency of the grown parts.

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Design and health care: a study of virtual design and direct metal laser sintering of titanium alloy for the production of customized facial implants

Australasian Medical Journal ◽

10.4066/amj.2009.81 ◽

2008 ◽

pp. 136-141

Author(s):

Liciane Sabadin Bertol ◽

Fabio Pinto Silva ◽

Wilson Kindlein Junior

Keyword(s):

Health Care ◽

Titanium Alloy ◽

Laser Sintering ◽

Direct Metal Laser Sintering ◽

Virtual Design

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Effect of Various Peening Methods on the Fatigue Properties of Titanium Alloy Ti6Al4V Manufactured by Direct Metal Laser Sintering and Electron Beam Melting

Materials ◽

10.3390/ma13102216 ◽

2020 ◽

Vol 13 (10) ◽

pp. 2216 ◽

Cited By ~ 3

Author(s):

Hitoshi Soyama ◽

Fumio Takeo

Keyword(s):

Titanium Alloy ◽

Electron Beam ◽

Fatigue Strength ◽

Shot Peening ◽

Electron Beam Melting ◽

Surface Hardness ◽

Laser Sintering ◽

Laser Peening ◽

Direct Metal Laser Sintering ◽

Titanium Alloy Ti6al4v

Titanium alloy Ti6Al4V manufactured by additive manufacturing (AM) is an attractive material, but the fatigue strength of AM Ti6Al4V is remarkably weak. Thus, post-processing is very important. Shot peening can improve the fatigue strength of metallic materials, and novel peening methods, such as cavitation peening and laser peening, have been developed. In the present paper, to demonstrate an improvement of the fatigue strength of AM Ti6Al4V, Ti6Al4V manufactured by direct metal laser sintering (DMLS) and electron beam melting (EBM) was treated by cavitation peening, laser peening, and shot peening, then tested by a plane bending fatigue test. To clarify the mechanism of the improvement of the fatigue strength of AM Ti6Al4V, the surface roughness, residual stress, and surface hardness were measured, and the surfaces with and without peening were also observed using a scanning electron microscope. It was revealed that the fatigue strength at N = 107 of Ti6Al4V manufactured by DMLS was slightly better than that of Ti6Al4V manufactured by EBM, and the fatigue strength of both the DMLS and EBM specimens was improved by about two times through cavitation peening, compared with the as-built ones. An experimental formula to estimate fatigue strength from the mechanical properties of a surface was proposed.

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