Control of the surface electron-beam alloying process by vibration monitoring

Abstract

The experimental results prove the ability to realize technology of chemical heat treatment of some materials by surface alloying using a wide-aperture low-energy high-current electron beam. Doped hardened layers were produced due to initiating exothermic chemical reactions between the base and the thin film covered on it. Nevertheless, it is quite difficult to control the process of surface electron-beam alloying due to the significant variation in the parameters of the microsecond electron beam pulse and the instability of its interaction with the processed material. It leads to significant random changes that occur spontaneously, regardless of the control system. In this situation, it is proposed to use the method based on monitoring of oscillations and acoustic emission, which has long proved to be an effective tool in the study of phase transformations and plastic deformation. The appearance of a process with high vibroacoustic activity under irradiation of plates made of pre-nitrated steel 08Cr17Ti with a deposited film Nb70Hf22Ti8 in the range of 11–22 kHz 10 ms after the electronic pulse was experimentally shown on this background. The source of this vibroacoustic signal is a change in the microstructure of the alloy, including the appearance of a martensitic component in the near-surface layer of the sample caused by the formation of nitride based on niobium. Tracking changes in the effective value of the vibroacoustic signal allow choosing the rational modes of irradiation with electron-beam surface alloying, involving the supply of maximum power, limited by the possibility of evaporation of the film with alloying components.

Milling of Electron Beam Melting Ti-6Al-4V by HSS Instrument with Combined Surface Treatment

“…The wear of the cutter is somewhat faster, which is consistent with the data [12]. The slower wear of the back surface of the tool subjected to a combined treatment consisting of ion nitriding to a depth of about 40 µm, surface alloying with niobium alloy, and subsequent application of a wear-resistant coating can be explained by the fact that the subsurface layer created under the coating containing fine-dispersed deformation martensite [13], has a higher hardness in combination with higher temperature resistance and better resistance to plastic deformation. Nitrides of Ti, Nb, and Hf form stable oxides.…”

Melting Thresholds of Materials Irradiated with a Wide Class of Pulsed Electron Beams

“…Equating T(0, τ) = T m in Expression (16) and making some transformations, the following is obtained:…”

“…In this paper, the main focus is on those PEB sources that are among the most promising for industrial applications (in the author's opinion). In particular, the 'RITM' PEB source is considered, which was developed at the Institute of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences [9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Back in the early 2000s, the license for its industrial production was sold to the Japanese 'SODICK' company, which produced the 'PIKA PF32A Finish Machine' industrial analogue.…”