A Study of the Structural Characteristics of Titanium Alloy Products Manufactured Using Additive Technologies by Combining the Selective Laser Melting and Direct Metal Deposition Methods

Abstract

Titanium alloy product manufacturing is traditionally considered to be a rather difficult task. Additive manufacturing technologies, which have recently become quite widespread, can ensure the manufacture of titanium alloys products of an arbitrary geometrical shape. During this study, we have developed a methodology for manufacturing titanium alloys products using additive technologies on FL-Clad-R-4 complex of laser melting of metals by combined Selective Laser Melting (SLM) and Direct Metal Deposition (DMD) methods. Ti–6Al–4V and Ti–6Al–4Mo–1V alloys were used for the manufacture of samples. We studied the microstructure of the obtained details and measured the microhardness of the samples. We discovered a gradient of the structure throughout the height of the details walls, which is connected with the peculiarities of thermal cycles of the technology used. This affected the microhardness values: in the upper part of the details, the microhardness is 10–25% higher (about 500 HV) than in the lower part (about 400 HV). Products made according to the developed technique do not have visible defects and pores. The obtained results indicate the competitiveness of the proposed methodology.

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

“…The study of the microstructure of the obtained samples showed that a mechanical mixture of α-and β-phases is formed as a result of melting (Figures 7 and 8). Earlier, we carried out work [26] in which we studied, in more detail, the phase composition of the samples obtained from the powder Ti-6Al-4V using similar fusion modes. The presence of two phases (α and β) in the structure is confirmed by XRD results.…”

“…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.…”

“…The LMD process is applicable to create infinitely large products of complex geometric shapes with small tolerances and high properties [25]. Moreover, the process of direct laser deposition is used to create new components of parts with high geometric complexity [26], which would require much more production hours or the possibility of creating a single whole product using detachable components to create it using traditional processing methods. Earlier, we carried out work [26] on growing a special item of parabolic shape by combining the selective laser melting and direct metal deposition.…”

“…Moreover, the process of direct laser deposition is used to create new components of parts with high geometric complexity [26], which would require much more production hours or the possibility of creating a single whole product using detachable components to create it using traditional processing methods. 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].…”