Electron Beam Welding Process for Ti6Al-4V Titanium Alloy

Abstract

The electron beam welding process of titanium alloys induces a series of physicochemical changes in the material that remain a relevant and necessary area of investigation. A necessary step performed after the electron beam welding process of titanium alloys in the Ti6Al-4V grade to mitigate the resulting thermal stresses is the post-weld heat-treatment process conducted through stress relieving. This study presents the comparative analysis results of the mechanical properties and structure of the Ti6Al-4V titanium alloy after electron beam welding and subsequent stress-relieving heat treatment at a temperature of 590 °C for 2 h. The analysis focused on the levels of mechanical properties such as microhardness in the heat-affected zone and weld, tensile strength, and microstructure analysis in the heat-affected zone and weld. The aim of the research was to answer the questions regarding whether the post-weld heat treatment through stress relieving after electron beam welding of the Ti6Al-4V titanium alloy would significantly affect the changes in mechanical properties and microstructure of the alloy and whether the applied welding speed in the study would cause a significant depletion of alloying elements in the material. During the course of the study, it was found that conducting the electron beam welding process at a speed of 8 mm/s resulted in a depletion of one of the alloying elements (aluminum) in the face area. However, the decrease in aluminum content was not significant and did not exceed the critical value of 6% specified in the material standards, which determined the material’s application based on its strength properties.

Microstructure, Variant Selection, and Mechanical Properties of Laser-Welded Ti-4Al-2V Joints

“…The yield strength and tensile strength of Joint (4) were 625 MPa and 729 MPa, respectively. Those of Joints ( 5) and ( 6) were slightly lower than those of Joint (4), about 615 MPa and 722 MPa for Joint (5), and 601 MPa and 720 MPa for Joint (6), respectively. Moreover, the rupture elongations of Joints ( 5) and ( 6) were both only about 7%, which was much lower than that of Joint (4) (~11%).…”

“…There was no significant difference in the type of texture and the intensity of the HAZ under different welding conditions. Figure 6c-e show the pole figures of the FZ for Joints (4)- (6). The types of microstructural texture formed under the three conditions were similar, including {0001} <10−10>, {11−20} <10−10>, and {11−20} <0001> plate textures.…”

“…Figure 4b2,c2,d2 show the HAZs of Joints ( 4)- (6). A clear gradient microstructure from the equiaxed grains on the side near the BM to needle like phases on the side near the FZ can be observed.…”

“…Numerous studies have shown that most titanium alloys exhibit good applicability and excellent welding performance when used to assemble complex structural components [3,4]. Titanium welding structures with excellent performance can be achieved through different welding methods [4][5][6].…”

Electron-Beam Welding of Titanium and Ti6Al4V Using Magnetron-Sputtered Nb, V, and Cu Fillers

“…The composition of the alloy includes 6% aluminum as an α-stabilizer and 4% vanadium as a β-stabilizer. The alloy is characterized by a higher phase transition temperature, much higher yield strength and tensile strength, a higher hardness, and lower thermal conductivity compared to pure titanium [6][7][8].…”