Microstructure Evolution Occurring in the Modied Metastable Titanium Alloy under High Current Pulsed Electron Beam Irradiation

Key words: 
• high current pulsed electron beam /
• metastable titanium alloy /
• surface treatment /
• microstructure /

Abstract: High current pulsed electron beam (HCPEB) surface treatment of a metastable titanium alloy that initially consisted of an + double-phase microstructure has been employed with a various treating parameters. The parameters taken are as follows: accelerating voltage, 27 kV; pulse numbers, 5, 10 and 25, respectively; pulse duration, 2 s. The microstructure and surface morphology changes occurring in the modified surface were investigated with optical microscopy, scanning electron microscopy, electron backscatter diffractometry and X-ray diffractometry techniques. We found that the sample surface showed a wavy aspect after 5 pulse treatment. After 25 pulses, the treated sample turned flatter and showed a lamellar structure. Meanwhile the initial phase in the surface layer diminished gradually while increasing the number of pulses. On the contrary, the ′′ martensite phase induced by the stress generated by the HCPEB treatment was found in melted layer of the treated samples.