Welding of titanium alloys

Abstract

Abstract. This article briefly summarises previous reports as well as some recent results on welding of various titanium alloys. Titanium is available in a wide range, hence, their properties and characteristics (including welding characteristics) may also varied significantly. The alloys studied represented three major areas; they are (1): unalloyed or commercially pure titanium (CP Ti), (2): near α and α+β alloys, and (3): β alloys. From our preliminary results, it can be reported that the structure of fusion zone (FZ) and heat affected zone (HAZ) of alloys from area (1) may change but their hardness remained, arguably, the same as the as-received material. Alloys from area (2) showed an increase in hardness in the FZ and HAZ areas due to the formation of α-prime or martensite, while alloys from area (3) experienced a reduction in hardness associated with dissolution of α phase leaving only retained β in the FZ. Further investigations are required to confirm these findings. Such information are very useful so that appropriate post welding heat treatment (PWHT) can be applied to improve their properties and performance.

Effects of Postprocess Hot Isostatic Pressing Treatments on the Mechanical Performance of EBM Fabricated TI-6Al-2Sn-4Zr-2Mo

“…In the present study, corresponding hardness also decreased somewhat inconsistently, as shown in Tables 3 and 4, and only varied by ~7%. Similar results for tensile property variation with acicular alpha-prime/alpha content have also been observed for both variously welded Ti-6Al-4V [28,29], as well as laser (SLM) and electron beam (EBM) processing and heat treatment of Ti64 [7,9,10], where additional anomalies and superior ductility have been achieved by the post-heat-treatment processing.…”

“…In the present study, corresponding hardness also decreased somewhat inconsistently, as shown in Tables 3 and 4, and only varied by ~7%. Similar results for tensile property variation with acicular alphaprime/alpha content have also been observed for both variously welded Ti-6Al-4V [28,29], as well as laser (SLM) and electron beam (EBM) processing and heat treatment of Ti64 [7,9,10], where additional anomalies and superior ductility have been achieved by the post-heat-treatment processing. It is apparent upon examining and comparing Tables 3 and 4, along with a somewhat systematic perusal of the comparative microstructure images in Figures 4-9, that there is a complex interplay between the grain structure (grain size) and the intragrain microstructures: acicular alpha-prime and alpha, including the contributions of bcc beta phase.…”

“…These features were observed more than three decades ago for the weld fusion zone of rapidly cooled Ti6242 alloy by Blaeslack and Mullins [20] where, at very high cooling rates (~500 • C/s), martensite dominated the microstructure, while an increasing volume fraction of acicular alpha emerged with decreasing cooling rates (by alpha-prime decomposition to alpha), creating alpha colonies at a cooling rate of ~7 • C/s. Similar microstructure features have been more recently observed in the laser-welding of both Ti6242 and Ti-6Al-4V (Ti64) alloys [21,[27][28][29], and the same acicular alpha-prime martensite microstructures have been recently observed for the selective-laser melting (SLM) of Ti64 [11,12,30]. It is also of interest to note that Ter Haar and Becker [11] and Yang, et al [13] have discussed a specific range of length regimes (from nano to micron) for alpha-prime martensite in Ti-6Al-4V, but their origin and specific influence on properties have not been discussed.…”

Dissimilar tungsten inert gas welding between Inconel 718 and commercially pure titanium using a vanadium interlayer

“…The epitaxial growth is demonstrated by all primary grains solidifying at the weld-metal interface, providing a competitive growth rate resulting in a coarse-grained microstructure at the center of the MZ4. Such similar epitaxial growth is explained in 54,55 and the epitaxial layer is clearly visible in Figure 7(d).…”

Effect of shielding gas on the properties of CP titanium Grade 2 laser weld joints

“…Typical yield strength ranged from 170 to 480 MPa. It came from the strengthening elements, i.e., oxygen and nitrogen in the form of α-phase accompanied by some minor β-phase due to the presence of Fe [13][14][15]. To date, under optimum processing conditions, the strength of the laser-welded titanium alloys can be close to that of the original material [16].…”