Авіаційно-космічна техніка та технологія (Dec 2018)
EFFECT OF THE POWER SUPPLY ON STRUCTURE AND PROPERTIES OF Ti-6Al-4V ALLOY PARTS DURING 3D-PRINTING
Abstract
The composition, structure and mechanical properties of samples obtained from the titanium alloy Ti-6Al-4V, by selective laser melting and electron beam melting processes regarding production of responsible aviation parts were carrying-out at present article. A comparative study of macro- and microstructure, mechanical properties has been carried out after inherent of Ti-6Al-4V heat treatment with or without prior hot isostatic pressing. It was established that the advent in specimens fractures and microstructure pores and non-melt inclusions of a granules condition obligatory hot isostatic pressing of a responsible parts when this kinds of defects significantly releases and correspondingly best complex of mechanical properties are obtained. The powders from titanium Ti-6Al-4V alloy were produce by inert gas (argon) spraying process and had a different particle sizing distribution: 20-50 microns for selective laser melting and 45-105 microns for electron beam melting. The microstructure of the specimens prepared using the studied production processes features an elongated lamellar alpha phase in the transformated epitaxially grown beta-matrix and is typical for Ti-6Al-4V alloy in a heat-treated condition. It has been noted that the lamellar alpha phase in the structure of the studied specimens after hot isostatic pressing is distinguished by larger sizes in width as compared to the specimens prior to hot isostatic pressing processing. Mechanical properties of the specimens produced by selective laser melting or electron beam melting processes meet the specification requirements. Hot isostatic pressing processing results in a remarkable improvement of the impact strength. Authors should be pointed out that application of additive technologies in the manufacture of aerospace parts requires extensive research&development works, and testing efforts to confirm repeatability of alloy characteristics. A mandatory procedure of the production process and material approval shall be conducted to ensure compliance with aircraft flight safety standards and regulations.
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