Effect of powder oxidation on the impact toughness of electron beam melting Ti-6Al-4V

(Cr, Fe)7C3/[Formula: see text]-Fe composite layer has been in situ synthesized on a low carbon steel surface by vacuum electron beam VEB irradiation. The synthesized samples were then subdued to different heat treatments to improve their impaired impact toughness. The microstructure, impact toughness and wear resistance of the heat-treated samples were studied by means of optical microscope (OM), X-ray diffraction (XRD), scanning electron microscope (SEM), microhardness tester, impact test machine and tribological tester. After heat treatment, the primary and eutectic carbides remained in their original shape and size, and a large number of secondary carbides precipitated in the iron matrix. Since the Widmanstatten ferrite in the heat affected zone (HAZ) transformed to fine ferrite completely, the impact toughness of the heat-treated samples increased significantly. The microhardness of the heat-treated samples decreased slightly due to the decreased chromium content in the iron matrix. The wear resistance of 1000[Formula: see text]C and 900[Formula: see text]C heat-treated samples was almost same with the as-synthesized sample. While the wear resistance of the 800[Formula: see text]C heat-treated one decreased slightly because part of the austenite matrix had transformed to ferrite matrix, which reduced the bonding of carbides particulates.

Download Full-text

ВПЛИВ ТЕХНОЛОГІЙ ПІДВЕДЕННЯ ЕНЕРГІЇ ПРИ 3D-ПРИНТИНГУ НА СТРУКТУРУ ТА ВЛАСТИВОСТІ ДЕТАЛЕЙ ЗІ СПЛАВУ Ti-6Al-4V

Aerospace technic and technology ◽

10.32620/aktt.2018.8.13 ◽

2018 ◽

pp. 86-90

Author(s):

Алексей Александрович Педаш ◽

Владимир Валериевич Клочихин ◽

Тамара Александровна Митина ◽

Валерий Григорьевич Шило

Keyword(s):

Mechanical Properties ◽

Electron Beam ◽

Selective Laser Melting ◽

Electron Beam Melting ◽

Melt Inclusions ◽

Hot Isostatic Pressing ◽

Alpha Phase ◽

Laser Melting ◽

Isostatic Pressing ◽

The Impact

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.

Download Full-text

Main Technological Parameters Influence of Selective Electron Beam Melting on Properties of Thin-Walled Titanium Alloy Samples

Materials Science Forum ◽

10.4028/www.scientific.net/msf.834.13 ◽

2015 ◽

Vol 834 ◽

pp. 13-20 ◽

Cited By ~ 1

Author(s):

Pavel Yurievich Peretyagin ◽

Vasily Petrovich Bolbukov ◽

Natalia Yurievna Cherkasova ◽

Alexander Victorovich Kabanov

Keyword(s):

Electron Beam ◽

Electron Beam Melting ◽

Aircraft Industry ◽

Technological Parameters ◽

Metallographic Examination ◽

Advanced Method ◽

Thin Walls ◽

Selective Electron Beam Melting ◽

Thin Walled ◽

The Impact

Selective electron beam melting has been considered as the most advanced method of additive manufacturing of workpieces made of titanium and titanium-based alloys for the aircraft industry. The impact of basic technological parameters on the thickness of thin walls obtained with the use of selective electron beam melting has considered. Metallographic examination of the experimental samples has been performed.

Download Full-text