Nanoobjects microscopy

Features of granulometric distribution of non-spherical powders of titanium alloys at within investigated fractions
Lemishka I.A.1, Trostianchyn A.M.1, Kulyk V.V. 1, Skrebtsov A.A.2, Kovbasyuk T.M.1
1 Lviv Polytechnic National University, Bandera st., 12 c. Lviv, 79013, Ukraine. E-mail: mzihor@ukr.net
2 Zaporizkyy National Technical University, Zhukovsky st., 64, c. Zaporizhzhia, 69063, Ukraine

One of the most promising materials for additive production in the field of aircraft building are powders of titanium alloys. An important requirement for them is the spherical shape of the particles. However, the cost of making such powders is more than 800 $/kg. Therefore, economically and technologically grounded task is to optimize the parameters of the technological process, in order to eliminate defects from the surface, as well as to achieve the maximum possible degree of homogeneity of non-spherical powder particles.
The morphology of the surface of titanium alloy powders was investigated using scanning electron microscopy on an EVO-40XVP microscope. The granulometric composition of powders of titanium alloys with particles of spherical and non-spherical shape was determined using a specialized image analysis complex called ImageJ. The degree of heterogeneity (polydispersity) of the powder was determined by the construction of the Gaussian curve on the basis of the histogram of the particle distribution in a certain fraction.
The study of the morphology of non-spherical powder particles has shown that some particles of titanium alloy powders of the brand VT6 are characterized by globular form of the surface. However, most of the particles have porous cup-shaped or lamellar form. In the case of non-spherical particles of titanium alloy powder of the brand VT20, ​​the structure of their surface is characterized by chips, which testify to the vibrations of the structure of the alloy during hydrogenation. There is a tendency according to which, when the particle size of the powder of the investigated alloy decreases, their shape approaches the spherical one.
Thus, taking into account the research results, the prospect of using titanium alloy powders of the brand VT20 with particles of a non-spherical form as an alternative raw material for additive production was shown.