Direct metal laser deposition of titanium powder Ti-6Al-4V

Abstract

Abstract. The paper presents the results of mechanical properties study of the material produced by direct metal laser deposition of VT6 titanium powder. The properties were determined by the results of stretching at tensile testing machine, as well as compared with the properties of the same rolled material. These results show that obtained samples have properties on the level or even higher than that ones of the samples obtained from the rolled material in a certain range of technological regimes. IntroductionTitanium alloys have already well approved themselves in chemical, marine, aerospace industries. They are very strong, able to withstand heavy loads and have reduced mass. In addition, titanium alloys are used for manufacturing implants and prostheses. Tissues around such implants are not subjects to change. They are resistant to corrosion in aggressive environment of the human body, and oxide coating on their surface prevents the escape of the implant ions into the body. However, the manufacture of titanium parts and implants is strictly individual task, as it is a material, which is difficult to process. This fact significantly increases the cost of a product. There is a significant interest in using different additive technology for manufacturing titanium parts in recent times. It is necessary to provide wide complex of researches and tests. Titanium alloys are used in the following additive technology: melting layer by layer powder by electron beam (EBM) [1,2] or laser (SLM, SLS methods) [3,4], feeding melted powder or wire by plasma arc [5,6] or laser (DMLD) [7,8]. We suggest using laser metal deposition technology for manufacturing of titanium parts. This technology involves melting of metallic powder feeding through the nozzle coaxially with the radiation. When the nozzle moves along the surface, new metal layer will be formed after solidification. Thus, it is possible to produce parts of the desired shape. The research presents the results of the mechanical properties study of the samples obtained by laser metal deposition technology by different technological modes.

Effect of the Ti6Al4V Alloy Track Trajectories on Mechanical Properties in Direct Metal Deposition

“…The porosity does not exceed 1% with direct laser melting, but the movement of the laser along different trajectories, with the possibility of texture formation in different metallographic planes [25][26][27], leads to the appearance of properties anisotropy [25].…”

“…Products from titanium alloys are manufactured using both selective laser melting (SLM) [11][12][13][14][15][16][17][18][19][20][21][22][23][24] and laser metal deposition (LMD) [25][26][27] technologies.…”

“…Earlier, we carried out work [26] on growing a special item of parabolic shape by combining the selective laser melting and direct metal deposition. There is no critical thermal effect on the entire remaining part due to spot heating by this method, in which the cost of creating a new product is reduced [27]. The direct laser melting process allows the gradient metal composites creation by mixing powders of different compositions in growing a product continuous process, thereby making it possible to obtain products that have no analogues on the market.…”