Deposition of Multicomponent Refractory-Metal-Containing Alloys

Abstract—The possibility of deposition of an Al–Zr–V–Nb coating in the form of a powder with a fraction of 0.063 mm and a humidity of 0.33%, which are measured using an AND MX-50 device, on a substrate made of 08Kh18N10 steel is considered. The deposition was carried out using a laser installation consisting of an LS-5 laser radiation source and a KUKA KR-60 ha robot in a protective argon atmosphere. Gas blowing was carried out 0.3 s before deposition and 1 s after it. For reliable bonding of the coating powder (Al–Zr–V–Nb) with the surface of the base material (08Kh18N10 steel), a mixture of powder with polyvinyl alcohol is applied onto the steel before melting. According to the data obtained on a Carl Zeiss EVO 40 scanning electron microscope, the optimum conditions of Al–Zr–V–Nb powder deposition on the base material corresponds to a power of 250 W, a processing speed of 0.5 m/s, and a coating thickness of 0.6 mm. At a lower power of 230 W, the coating cannot melt qualitatively; as a result, insufficient melting of the base metal by the coating metal (adhesion) occurs and partial separation takes place. If the power is increased to 270 W, the base and coating materials interact with each other well and create a high-strength coating monolayer, just as that under the optimum conditions. However, cracking occurs and microcracks appear during cooling because of a significant difference in the cooling rates (08Kh18N10 steel plate does not have time to cool at the rate of the coating material). Thus, there is a need to further increase the number of passes or to perform additional melting to create a reliable coating with no discontinuities and islands. Vickers microhardness (HV) measurements during the deposition of an Al–Zr–V–Nb coating demonstrate an increase in HV by more than two times compared to the base material, which is a sufficient reason for using an Al–Zr–V–Nb powder as a strengthening coating for 08Kh18N10 steel.