Effect of high current pulsed electron beam irradiation on wear and corrosion resistance of Ti6Al4V

The effect of large-area pulsed electron beam melting on the corrosion and microstructure of a Ti6Al4V alloy

“…In terms of improving the surface wettability, particularly for applications in the biomedical sector where wettability and surface micro--architecture lead to greater osseo--integration of cellular material with implant prostheses [25,26], it seems that low energy dosing of the surface was preferential. Within these grains, the presence of needle like α' hexagonal martensitic phases were observed contained within prior β grain boundaries and were consistent to previous studies using this technique [17,18,22,23]. The formation of this phase occurs due to the rapid quenching rate of the near surface, effecting a diffusionless β to α' phase transformation at a high enough cooling rate to preclude transformation by nucleation and growth.…”

“…This was largely consistent with previous LAEBM on the same alloy by Gao [17] and Okada et al [20], the latter showing sharp edges resulting from a ball end mill were rounded at a beam energy of 1.2J/cm 2 , without a significant change in the overall RZ value. Absolute values of surface roughness, Ra, in this study were lower than that observed by Guo et al [18], however it must be noted that their incident beam energies were notably higher (9 J/cm 2 ), resulting in large surface crater formation.…”

“…In contrast, corrosion rates of LAEBM treated surface in this study were as much as two orders of magnitude lower, highlighting the influence of differences in alloy chemistry on corrosion processes. There is also evidence [18,23] that extending the number of pulse treatments beyond a certain threshold results in a reduction in the observed corrosion resistance, highlighted in the present study by a reduction in the corrosion rate, Table 2, for the 25 pulse treatment. This may be due to changes in cooling rate associated with samples treated with a large number of pulses affecting the resulting surface microstructure development, however, clearly more work is required to verify this.…”

“…It was shown in Table 2 to a single phase α' structure, rather than a dual phase α + β was believed to be a direct contributor to the lower corrosion rates [18]. Studies into the rapid quenching of Ti--6Al--4V alloys have shown evidence that such martensitic structures do indeed exhibit lower corrosion rates [12,29].…”

Surface modification of Ti alloy by electro-explosive alloying and electron-beam treatment

“…The interaction of high current pulsed electron beam with materials has recently received enormous attention for surface treatment [3][4][5][6][7]. The high current pulsed electron beam treatment (EBT) is a new surface modification process and can be applied in many fields.…”